From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 21:33:14 +0200
Subject: Adding upstream version 115.7.0esr.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../tests/non262/Intl/NumberFormat/StringBuffer.js |  37 ++
 .../tests/non262/Intl/NumberFormat/bigint-int64.js |  40 +++
 js/src/tests/non262/Intl/NumberFormat/browser.js   |   0
 js/src/tests/non262/Intl/NumberFormat/call.js      | 184 ++++++++++
 .../Intl/NumberFormat/construct-newtarget.js       |  81 +++++
 .../non262/Intl/NumberFormat/cross-compartment.js  |  70 ++++
 .../Intl/NumberFormat/currency-narrow-symbol.js    |  40 +++
 .../Intl/NumberFormat/currency-sign-accounting.js  | 192 +++++++++++
 .../NumberFormat/duplicate-singleton-variant.js    |  49 +++
 .../Intl/NumberFormat/format-as-code-or-name.js    |  75 +++++
 .../non262/Intl/NumberFormat/format-string.js      | 150 +++++++++
 js/src/tests/non262/Intl/NumberFormat/format.js    |  55 +++
 .../non262/Intl/NumberFormat/formatRange-BigInt.js | 150 +++++++++
 .../tests/non262/Intl/NumberFormat/formatRange.js  | 296 ++++++++++++++++
 ...ormatRangeToParts-approximately-sign-compact.js |  34 ++
 ...rmatRangeToParts-approximately-sign-currency.js |  34 ++
 ...ormatRangeToParts-approximately-sign-percent.js |  34 ++
 ...tRangeToParts-approximately-sign-signDisplay.js |  34 ++
 .../formatRangeToParts-approximately-sign-unit.js  |  41 +++
 .../formatRangeToParts-approximately-sign.js       |  34 ++
 .../non262/Intl/NumberFormat/formatRangeToParts.js | 174 ++++++++++
 .../non262/Intl/NumberFormat/formatToParts.js      | 357 ++++++++++++++++++++
 .../non262/Intl/NumberFormat/formatting-NaN.js     |  35 ++
 .../NumberFormat/negativeZeroFractionDigits.js     |  21 ++
 .../Intl/NumberFormat/notation-compact-long.js     | 139 ++++++++
 .../Intl/NumberFormat/notation-compact-short.js    | 136 ++++++++
 .../notation-compact-with-fraction-digits.js       |  17 +
 .../Intl/NumberFormat/notation-engineering.js      | 136 ++++++++
 .../Intl/NumberFormat/notation-scientific.js       | 136 ++++++++
 .../Intl/NumberFormat/numberingSystem-format.js    |  18 +
 .../Intl/NumberFormat/numberingSystem-option.js    |  60 ++++
 .../Intl/NumberFormat/options-emulate-undefined.js |  13 +
 .../Intl/NumberFormat/remove-unicode-extensions.js |  25 ++
 .../non262/Intl/NumberFormat/rounding-increment.js | 102 ++++++
 .../non262/Intl/NumberFormat/rounding-mode.js      | 287 ++++++++++++++++
 .../non262/Intl/NumberFormat/rounding-priority.js  | 132 ++++++++
 js/src/tests/non262/Intl/NumberFormat/shell.js     |  77 +++++
 .../tests/non262/Intl/NumberFormat/sign-display.js | 187 +++++++++++
 .../Intl/NumberFormat/significantDigitsOfZero.js   |  38 +++
 .../non262/Intl/NumberFormat/supportedLocalesOf.js | 371 +++++++++++++++++++++
 .../tests/non262/Intl/NumberFormat/toStringTag.js  |  29 ++
 .../Intl/NumberFormat/trailing-zero-display.js     |  98 ++++++
 .../NumberFormat/unit-compound-combinations.js     |  65 ++++
 .../unit-formatToParts-has-unit-field.js           |  90 +++++
 .../non262/Intl/NumberFormat/unit-well-formed.js   | 267 +++++++++++++++
 js/src/tests/non262/Intl/NumberFormat/unit.js      | 104 ++++++
 .../tests/non262/Intl/NumberFormat/unwrapping.js   | 248 ++++++++++++++
 .../Intl/NumberFormat/use-grouping-bool-string.js  |  10 +
 .../tests/non262/Intl/NumberFormat/use-grouping.js |  97 ++++++
 49 files changed, 5099 insertions(+)
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/StringBuffer.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/bigint-int64.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/browser.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/call.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/construct-newtarget.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/cross-compartment.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/currency-narrow-symbol.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/currency-sign-accounting.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/duplicate-singleton-variant.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/format-as-code-or-name.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/format-string.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/format.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRange-BigInt.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRange.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-compact.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-currency.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-percent.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-signDisplay.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-unit.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatRangeToParts.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatToParts.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/formatting-NaN.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/negativeZeroFractionDigits.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/notation-compact-long.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/notation-compact-short.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/notation-compact-with-fraction-digits.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/notation-engineering.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/notation-scientific.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/numberingSystem-format.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/numberingSystem-option.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/options-emulate-undefined.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/remove-unicode-extensions.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/rounding-increment.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/rounding-mode.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/rounding-priority.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/shell.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/sign-display.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/significantDigitsOfZero.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/supportedLocalesOf.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/toStringTag.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/trailing-zero-display.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/unit-compound-combinations.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/unit-formatToParts-has-unit-field.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/unit-well-formed.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/unit.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/unwrapping.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/use-grouping-bool-string.js
 create mode 100644 js/src/tests/non262/Intl/NumberFormat/use-grouping.js

(limited to 'js/src/tests/non262/Intl/NumberFormat')

diff --git a/js/src/tests/non262/Intl/NumberFormat/StringBuffer.js b/js/src/tests/non262/Intl/NumberFormat/StringBuffer.js
new file mode 100644
index 0000000000..70aaa7bd75
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/StringBuffer.js
@@ -0,0 +1,37 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The implementation of the format function uses the C++ StringBuffer class,
+// which changes its storage model at 32 characters, and uses it in a way which
+// also means that there's no room for null-termination at this limit.
+// This test makes sure that none of this affects the output.
+
+var format = new Intl.NumberFormat("it-IT", {minimumFractionDigits: 1});
+
+assertEq(format.format(1123123123123123123123.1), "1.123.123.123.123.123.100.000,0");
+assertEq(format.format(12123123123123123123123.1), "12.123.123.123.123.122.000.000,0");
+assertEq(format.format(123123123123123123123123.1), "123.123.123.123.123.120.000.000,0");
+
+// Ensure the ICU output matches Number.prototype.toFixed.
+function formatToFixed(x) {
+    var mfd = format.resolvedOptions().maximumFractionDigits;
+    var s = x.toFixed(mfd);
+
+    // To keep it simple we assume |s| is always in exponential form.
+    var m = s.match(/^(\d)\.(\d+)e\+(\d+)$/);
+    assertEq(m !== null, true);
+    s = m[1] + m[2].padEnd(m[3], "0");
+
+    // Group digits and append fractional part.
+    m = s.match(/\d{1,3}(?=(?:\d{3})*$)/g);
+    assertEq(m !== null, true);
+    return m.join(".") + ",0";
+}
+
+assertEq(formatToFixed(1123123123123123123123.1), "1.123.123.123.123.123.100.000,0");
+assertEq(formatToFixed(12123123123123123123123.1), "12.123.123.123.123.122.000.000,0");
+assertEq(formatToFixed(123123123123123123123123.1), "123.123.123.123.123.120.000.000,0");
+
+reportCompare(0, 0, "ok");
diff --git a/js/src/tests/non262/Intl/NumberFormat/bigint-int64.js b/js/src/tests/non262/Intl/NumberFormat/bigint-int64.js
new file mode 100644
index 0000000000..7b670d0873
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/bigint-int64.js
@@ -0,0 +1,40 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Ensure the int64_t optimization when formatting a BigInt value works correctly by testing with
+// various integers around the (u)int[32,64] limits.
+
+const limits = {
+    int32: {
+        min: -0x80000000n,
+        max:  0x7FFFFFFFn,
+    },
+    uint32: {
+        min: 0n,
+        max: 0xFFFFFFFFn
+    },
+    int64: {
+        min: -0x8000000000000000n,
+        max:  0x7FFFFFFFFFFFFFFFn,
+    },
+    uint64: {
+        min: 0n,
+        max: 0xFFFFFFFFFFFFFFFFn
+    },
+};
+
+const nf = new Intl.NumberFormat("en", {useGrouping: false});
+
+const diff = 10n;
+
+for (const int of Object.values(limits)) {
+    for (let i = -diff; i <= diff; ++i) {
+        let n = int.min + i;
+        assertEq(nf.format(n), n.toString());
+
+        let m = int.max + i;
+        assertEq(nf.format(m), m.toString());
+    }
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/browser.js b/js/src/tests/non262/Intl/NumberFormat/browser.js
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/js/src/tests/non262/Intl/NumberFormat/call.js b/js/src/tests/non262/Intl/NumberFormat/call.js
new file mode 100644
index 0000000000..14ecf99eb5
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/call.js
@@ -0,0 +1,184 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+function IsIntlService(c) {
+    return typeof c === "function" &&
+           c.hasOwnProperty("prototype") &&
+           c.prototype.hasOwnProperty("resolvedOptions");
+}
+
+function IsObject(o) {
+    return Object(o) === o;
+}
+
+function IsPrimitive(o) {
+    return Object(o) !== o;
+}
+
+function thisValues() {
+    const intlConstructors = Object.getOwnPropertyNames(Intl).map(name => Intl[name]).filter(IsIntlService);
+
+    return [
+        // Primitive values.
+        ...[undefined, null, true, "abc", Symbol(), 123],
+
+        // Object values.
+        ...[{}, [], /(?:)/, function(){}, new Proxy({}, {})],
+
+        // Intl objects.
+        ...[].concat(...intlConstructors.map(ctor => {
+            let args = [];
+            if (ctor === Intl.DisplayNames) {
+                // Intl.DisplayNames can't be constructed without any arguments.
+                args = [undefined, {type: "language"}];
+            }
+
+            return [
+                // Instance of an Intl constructor.
+                new ctor(...args),
+
+                // Instance of a subclassed Intl constructor.
+                new class extends ctor {}(...args),
+
+                // Object inheriting from an Intl constructor prototype.
+                Object.create(ctor.prototype),
+
+                // Intl object not inheriting from its default prototype.
+                Object.setPrototypeOf(new ctor(...args), Object.prototype),
+            ];
+        })),
+    ];
+}
+
+const intlFallbackSymbol = Object.getOwnPropertySymbols(Intl.NumberFormat.call(Object.create(Intl.NumberFormat.prototype)))[0];
+
+// Invoking [[Call]] for Intl.NumberFormat returns a new instance unless called
+// with an instance inheriting from Intl.NumberFormat.prototype.
+for (let thisValue of thisValues()) {
+    let obj = Intl.NumberFormat.call(thisValue);
+
+    if (!Intl.NumberFormat.prototype.isPrototypeOf(thisValue)) {
+        assertEq(Object.is(obj, thisValue), false);
+        assertEq(obj instanceof Intl.NumberFormat, true);
+        if (IsObject(thisValue))
+            assertEqArray(Object.getOwnPropertySymbols(thisValue), []);
+    } else {
+        assertEq(Object.is(obj, thisValue), true);
+        assertEq(obj instanceof Intl.NumberFormat, true);
+        assertEqArray(Object.getOwnPropertySymbols(thisValue), [intlFallbackSymbol]);
+    }
+}
+
+// Intl.NumberFormat uses the legacy Intl constructor compromise semantics.
+// - Test when InstanceofOperator(thisValue, %NumberFormat%) returns true.
+for (let thisValue of thisValues().filter(IsObject)) {
+    let isPrototypeOf = Intl.NumberFormat.prototype.isPrototypeOf(thisValue);
+    let hasInstanceCalled = false;
+    Object.defineProperty(Intl.NumberFormat, Symbol.hasInstance, {
+        value() {
+            assertEq(hasInstanceCalled, false);
+            hasInstanceCalled = true;
+            return true;
+        }, configurable: true
+    });
+    let obj = Intl.NumberFormat.call(thisValue);
+    delete Intl.NumberFormat[Symbol.hasInstance];
+
+    assertEq(Object.is(obj, thisValue), isPrototypeOf);
+    assertEq(hasInstanceCalled, false);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), isPrototypeOf ? [intlFallbackSymbol] : []);
+}
+// - Test when InstanceofOperator(thisValue, %NumberFormat%) returns false.
+for (let thisValue of thisValues().filter(IsObject)) {
+    let isPrototypeOf = Intl.NumberFormat.prototype.isPrototypeOf(thisValue);
+    let hasInstanceCalled = false;
+    Object.defineProperty(Intl.NumberFormat, Symbol.hasInstance, {
+        value() {
+            assertEq(hasInstanceCalled, false);
+            hasInstanceCalled = true;
+            return false;
+        }, configurable: true
+    });
+    let obj = Intl.NumberFormat.call(thisValue);
+    delete Intl.NumberFormat[Symbol.hasInstance];
+
+    assertEq(Object.is(obj, thisValue), isPrototypeOf);
+    assertEq(obj instanceof Intl.NumberFormat, true);
+    assertEq(hasInstanceCalled, false);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), isPrototypeOf ? [intlFallbackSymbol] : []);
+}
+// - Test with primitive values.
+for (let thisValue of thisValues().filter(IsPrimitive)) {
+    // Ensure @@hasInstance is not called.
+    Object.defineProperty(Intl.NumberFormat, Symbol.hasInstance, {
+        value() { assertEq(true, false); }, configurable: true
+    });
+    let obj = Intl.NumberFormat.call(thisValue);
+    delete Intl.NumberFormat[Symbol.hasInstance];
+
+    assertEq(Object.is(obj, thisValue), false);
+    assertEq(obj instanceof Intl.NumberFormat, true);
+}
+
+// Throws an error when attempting to install [[FallbackSymbol]] twice.
+{
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), []);
+
+    assertEq(Intl.NumberFormat.call(thisValue), thisValue);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), [intlFallbackSymbol]);
+
+    assertThrowsInstanceOf(() => Intl.NumberFormat.call(thisValue), TypeError);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), [intlFallbackSymbol]);
+}
+
+// Throws an error when the thisValue is non-extensible.
+{
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    Object.preventExtensions(thisValue);
+
+    assertThrowsInstanceOf(() => Intl.NumberFormat.call(thisValue), TypeError);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), []);
+}
+
+// [[FallbackSymbol]] is installed as a frozen property holding an Intl.NumberFormat instance.
+{
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    Intl.NumberFormat.call(thisValue);
+
+    let desc = Object.getOwnPropertyDescriptor(thisValue, intlFallbackSymbol);
+    assertEq(desc !== undefined, true);
+    assertEq(desc.writable, false);
+    assertEq(desc.enumerable, false);
+    assertEq(desc.configurable, false);
+    assertEq(desc.value instanceof Intl.NumberFormat, true);
+}
+
+// Ensure [[FallbackSymbol]] is installed last by changing the [[Prototype]]
+// during initialization.
+{
+    let thisValue = {};
+    let options = {
+        get useGrouping() {
+            Object.setPrototypeOf(thisValue, Intl.NumberFormat.prototype);
+            return false;
+        }
+    };
+    let obj = Intl.NumberFormat.call(thisValue, undefined, options);
+    assertEq(Object.is(obj, thisValue), true);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), [intlFallbackSymbol]);
+}
+{
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    let options = {
+        get useGrouping() {
+            Object.setPrototypeOf(thisValue, Object.prototype);
+            return false;
+        }
+    };
+    let obj = Intl.NumberFormat.call(thisValue, undefined, options);
+    assertEq(Object.is(obj, thisValue), false);
+    assertEqArray(Object.getOwnPropertySymbols(thisValue), []);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/construct-newtarget.js b/js/src/tests/non262/Intl/NumberFormat/construct-newtarget.js
new file mode 100644
index 0000000000..0053b2737e
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/construct-newtarget.js
@@ -0,0 +1,81 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+// Test subclassing %Intl.NumberFormat% works correctly.
+class MyNumberFormat extends Intl.NumberFormat {}
+
+var obj = new MyNumberFormat();
+assertEq(obj instanceof MyNumberFormat, true);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), MyNumberFormat.prototype);
+
+obj = Reflect.construct(MyNumberFormat, []);
+assertEq(obj instanceof MyNumberFormat, true);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), MyNumberFormat.prototype);
+
+obj = Reflect.construct(MyNumberFormat, [], MyNumberFormat);
+assertEq(obj instanceof MyNumberFormat, true);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), MyNumberFormat.prototype);
+
+obj = Reflect.construct(MyNumberFormat, [], Intl.NumberFormat);
+assertEq(obj instanceof MyNumberFormat, false);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), Intl.NumberFormat.prototype);
+
+
+// Set a different constructor as NewTarget.
+obj = Reflect.construct(MyNumberFormat, [], Array);
+assertEq(obj instanceof MyNumberFormat, false);
+assertEq(obj instanceof Intl.NumberFormat, false);
+assertEq(obj instanceof Array, true);
+assertEq(Object.getPrototypeOf(obj), Array.prototype);
+
+obj = Reflect.construct(Intl.NumberFormat, [], Array);
+assertEq(obj instanceof Intl.NumberFormat, false);
+assertEq(obj instanceof Array, true);
+assertEq(Object.getPrototypeOf(obj), Array.prototype);
+
+
+// The prototype defaults to %NumberFormatPrototype% if null.
+function NewTargetNullPrototype() {}
+NewTargetNullPrototype.prototype = null;
+
+obj = Reflect.construct(Intl.NumberFormat, [], NewTargetNullPrototype);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), Intl.NumberFormat.prototype);
+
+obj = Reflect.construct(MyNumberFormat, [], NewTargetNullPrototype);
+assertEq(obj instanceof MyNumberFormat, false);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), Intl.NumberFormat.prototype);
+
+
+// "prototype" property is retrieved exactly once.
+var trapLog = [], getLog = [];
+var ProxiedConstructor = new Proxy(Intl.NumberFormat, new Proxy({
+    get(target, propertyKey, receiver) {
+        getLog.push(propertyKey);
+        return Reflect.get(target, propertyKey, receiver);
+    }
+}, {
+    get(target, propertyKey, receiver) {
+        trapLog.push(propertyKey);
+        return Reflect.get(target, propertyKey, receiver);
+    }
+}));
+
+obj = Reflect.construct(Intl.NumberFormat, [], ProxiedConstructor);
+assertEqArray(trapLog, ["get"]);
+assertEqArray(getLog, ["prototype"]);
+assertEq(obj instanceof Intl.NumberFormat, true);
+assertEq(Object.getPrototypeOf(obj), Intl.NumberFormat.prototype);
+
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);
diff --git a/js/src/tests/non262/Intl/NumberFormat/cross-compartment.js b/js/src/tests/non262/Intl/NumberFormat/cross-compartment.js
new file mode 100644
index 0000000000..806f889d6f
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/cross-compartment.js
@@ -0,0 +1,70 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+var otherGlobal = newGlobal();
+
+var numberFormat = new Intl.NumberFormat();
+var ccwNumberFormat = new otherGlobal.Intl.NumberFormat();
+
+// Test Intl.NumberFormat.prototype.format with a CCW object.
+var Intl_NumberFormat_format_get = Object.getOwnPropertyDescriptor(Intl.NumberFormat.prototype, "format").get;
+
+assertEq(Intl_NumberFormat_format_get.call(ccwNumberFormat)(0),
+         Intl_NumberFormat_format_get.call(numberFormat)(0));
+
+// Test Intl.NumberFormat.prototype.formatToParts with a CCW object.
+var Intl_NumberFormat_formatToParts = Intl.NumberFormat.prototype.formatToParts;
+
+assertEq(deepEqual(Intl_NumberFormat_formatToParts.call(ccwNumberFormat, 0),
+                   Intl_NumberFormat_formatToParts.call(numberFormat, 0)),
+         true);
+
+// Test Intl.NumberFormat.prototype.resolvedOptions with a CCW object.
+var Intl_NumberFormat_resolvedOptions = Intl.NumberFormat.prototype.resolvedOptions;
+
+assertEq(deepEqual(Intl_NumberFormat_resolvedOptions.call(ccwNumberFormat),
+                   Intl_NumberFormat_resolvedOptions.call(numberFormat)),
+         true);
+
+// Special case for Intl.NumberFormat: The Intl fallback symbol.
+
+function fallbackSymbol(global) {
+    var NF = global.Intl.NumberFormat;
+    return Object.getOwnPropertySymbols(NF.call(Object.create(NF.prototype)))[0];
+}
+
+const intlFallbackSymbol = fallbackSymbol(this);
+const otherIntlFallbackSymbol = fallbackSymbol(otherGlobal);
+assertEq(intlFallbackSymbol === otherIntlFallbackSymbol, false);
+
+// Test when the fallback symbol points to a CCW NumberFormat object.
+var objWithFallbackCCWNumberFormat = {
+    __proto__: Intl.NumberFormat.prototype,
+    [intlFallbackSymbol]: ccwNumberFormat,
+};
+
+assertEq(Intl_NumberFormat_format_get.call(objWithFallbackCCWNumberFormat)(0),
+         Intl_NumberFormat_format_get.call(numberFormat)(0));
+
+assertEq(deepEqual(Intl_NumberFormat_resolvedOptions.call(objWithFallbackCCWNumberFormat),
+                   Intl_NumberFormat_resolvedOptions.call(numberFormat)),
+         true);
+
+// Ensure the fallback symbol(s) are not accessed for CCW NumberFormat objects.
+var ccwNumberFormatWithPoisonedFallback = new otherGlobal.Intl.NumberFormat();
+Object.setPrototypeOf(ccwNumberFormatWithPoisonedFallback, Intl.NumberFormat.prototype);
+Object.defineProperty(ccwNumberFormatWithPoisonedFallback, intlFallbackSymbol, {
+    get() { throw new Error(); }
+});
+Object.defineProperty(ccwNumberFormatWithPoisonedFallback, otherIntlFallbackSymbol, {
+    get() { throw new Error(); }
+});
+
+assertEq(Intl_NumberFormat_format_get.call(ccwNumberFormatWithPoisonedFallback)(0),
+         Intl_NumberFormat_format_get.call(numberFormat)(0));
+
+assertEq(deepEqual(Intl_NumberFormat_resolvedOptions.call(ccwNumberFormatWithPoisonedFallback),
+                   Intl_NumberFormat_resolvedOptions.call(numberFormat)),
+         true);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/currency-narrow-symbol.js b/js/src/tests/non262/Intl/NumberFormat/currency-narrow-symbol.js
new file mode 100644
index 0000000000..bf2b9adcd8
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/currency-narrow-symbol.js
@@ -0,0 +1,40 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Integer, Decimal, Fraction, Currency, Literal,
+} = NumberFormatParts;
+
+const testcases = [
+    {
+        locale: "en-CA",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencyDisplay: "narrowSymbol",
+        },
+        values: [
+            {value: 123, string: "US$123.00",
+             parts: [Currency("US$"), Integer("123"), Decimal("."), Fraction("00")]},
+        ],
+    },
+
+    // And for comparison "symbol" currency-display.
+
+    {
+        locale: "en-CA",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencyDisplay: "symbol",
+        },
+        values: [
+            {value: 123, string: "US$123.00",
+             parts: [Currency("US$"), Integer("123"), Decimal("."), Fraction("00")]},
+        ],
+    },
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/currency-sign-accounting.js b/js/src/tests/non262/Intl/NumberFormat/currency-sign-accounting.js
new file mode 100644
index 0000000000..6f91d6edd4
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/currency-sign-accounting.js
@@ -0,0 +1,192 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Decimal, Fraction,
+    Currency, Literal,
+} = NumberFormatParts;
+
+const testcases = [
+    // "auto": Show the sign on negative numbers only.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "auto",
+        },
+        values: [
+            {value: +0, string: "$0.00",
+             parts: [Currency("$"), Integer("0"), Decimal("."), Fraction("00")]},
+            {value: -0, string: "($0.00)",
+             parts: [Literal("("), Currency("$"), Integer("0"), Decimal("."), Fraction("00"), Literal(")")]},
+
+            {value:  1, string: "$1.00",
+             parts: [Currency("$"), Integer("1"), Decimal("."), Fraction("00")]},
+            {value: -1, string: "($1.00)",
+             parts: [Literal("("), Currency("$"), Integer("1"), Decimal("."), Fraction("00"), Literal(")")]},
+
+            {value:  Infinity, string: "$∞", parts: [Currency("$"), Inf("∞")]},
+            {value: -Infinity, string: "($∞)", parts: [Literal("("), Currency("$"), Inf("∞"), Literal(")")]},
+
+            {value:  NaN, string: "$NaN", parts: [Currency("$"), Nan("NaN")]},
+            {value: -NaN, string: "$NaN", parts: [Currency("$"), Nan("NaN")]},
+        ],
+    },
+
+    // "never": Show the sign on neither positive nor negative numbers.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "never",
+        },
+        values: [
+            {value: +0, string: "$0.00", parts: [Currency("$"), Integer("0"), Decimal("."), Fraction("00")]},
+            {value: -0, string: "$0.00", parts: [Currency("$"), Integer("0"), Decimal("."), Fraction("00")]},
+
+            {value:  1, string: "$1.00", parts: [Currency("$"), Integer("1"), Decimal("."), Fraction("00")]},
+            {value: -1, string: "$1.00", parts: [Currency("$"), Integer("1"), Decimal("."), Fraction("00")]},
+
+            {value:  Infinity, string: "$∞", parts: [Currency("$"), Inf("∞")]},
+            {value: -Infinity, string: "$∞", parts: [Currency("$"), Inf("∞")]},
+
+            {value:  NaN, string: "$NaN", parts: [Currency("$"), Nan("NaN")]},
+            {value: -NaN, string: "$NaN", parts: [Currency("$"), Nan("NaN")]},
+        ],
+    },
+
+    // "always": Show the sign on positive and negative numbers including zero.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "always",
+        },
+        values: [
+            {value: +0, string: "+$0.00",
+             parts: [PlusSign("+"), Currency("$"), Integer("0"), Decimal("."), Fraction("00")]},
+            {value: -0, string: "($0.00)",
+             parts: [Literal("("), Currency("$"), Integer("0"), Decimal("."), Fraction("00"), Literal(")")]},
+
+            {value:  1, string: "+$1.00",
+             parts: [PlusSign("+"), Currency("$"), Integer("1"), Decimal("."), Fraction("00")]},
+            {value: -1, string: "($1.00)",
+             parts: [Literal("("), Currency("$"), Integer("1"), Decimal("."), Fraction("00"), Literal(")")]},
+
+            {value:  Infinity, string: "+$∞", parts: [PlusSign("+"), Currency("$"), Inf("∞")]},
+            {value: -Infinity, string: "($∞)", parts: [Literal("("), Currency("$"), Inf("∞"), Literal(")")]},
+
+            {value:  NaN, string: "+$NaN", parts: [PlusSign("+"), Currency("$"), Nan("NaN")]},
+            {value: -NaN, string: "+$NaN", parts: [PlusSign("+"), Currency("$"), Nan("NaN")]},
+        ],
+    },
+
+    // "exceptZero": Show the sign on positive and negative numbers but not zero.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "exceptZero",
+        },
+        values: [
+            {value: +0, string: "$0.00",
+             parts: [Currency("$"), Integer("0"), Decimal("."), Fraction("00")]},
+            {value: -0, string: "$0.00",
+             parts: [Currency("$"), Integer("0"), Decimal("."), Fraction("00")]},
+
+            {value:  1, string: "+$1.00",
+             parts: [PlusSign("+"), Currency("$"), Integer("1"), Decimal("."), Fraction("00")]},
+            {value: -1, string: "($1.00)",
+             parts: [Literal("("), Currency("$"), Integer("1"), Decimal("."), Fraction("00"), Literal(")")]},
+
+            {value:  Infinity, string: "+$∞", parts: [PlusSign("+"), Currency("$"), Inf("∞")]},
+            {value: -Infinity, string: "($∞)", parts: [Literal("("), Currency("$"), Inf("∞"), Literal(")")]},
+
+            {value:  NaN, string: "$NaN", parts: [Currency("$"), Nan("NaN")]},
+            {value: -NaN, string: "$NaN", parts: [Currency("$"), Nan("NaN")]},
+        ],
+    },
+
+    // Tests with suppressed fractional digits.
+
+    // "auto": Show the sign on negative numbers only.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "auto",
+            minimumFractionDigits: 0,
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: +0.1, string: "$0", parts: [Currency("$"), Integer("0")]},
+            {value: -0.1, string: "($0)", parts: [Literal("("), Currency("$"), Integer("0"), Literal(")")]},
+        ],
+    },
+
+    // "never": Show the sign on neither positive nor negative numbers.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "never",
+            minimumFractionDigits: 0,
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: +0.1, string: "$0", parts: [Currency("$"), Integer("0")]},
+            {value: -0.1, string: "$0", parts: [Currency("$"), Integer("0")]},
+        ],
+    },
+
+    // "always": Show the sign on positive and negative numbers including zero.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "always",
+            minimumFractionDigits: 0,
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: +0.1, string: "+$0", parts: [PlusSign("+"), Currency("$"), Integer("0")]},
+            {value: -0.1, string: "($0)", parts: [Literal("("), Currency("$"), Integer("0"), Literal(")")]},
+        ],
+    },
+
+    // "exceptZero": Show the sign on positive and negative numbers but not zero.
+    {
+        locale: "en",
+        options: {
+            style: "currency",
+            currency: "USD",
+            currencySign: "accounting",
+            signDisplay: "exceptZero",
+            minimumFractionDigits: 0,
+            maximumFractionDigits: 0,
+        },
+
+        values: [
+            {value: +0.1, string: "$0", parts: [Currency("$"), Integer("0")]},
+            {value: -0.1, string: "$0", parts: [Currency("$"), Integer("0")]},
+        ],
+    }
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/duplicate-singleton-variant.js b/js/src/tests/non262/Intl/NumberFormat/duplicate-singleton-variant.js
new file mode 100644
index 0000000000..42bf78c3fe
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/duplicate-singleton-variant.js
@@ -0,0 +1,49 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Check for duplicate variants and singletons case-insensitively, but don't
+// check in privateuse components.
+
+function checkInvalidLocale(locale)
+{
+  try
+  {
+    new Intl.NumberFormat(locale);
+    throw new Error("didn't throw");
+  }
+  catch (e)
+  {
+    assertEq(e instanceof RangeError, true,
+             "expected RangeError for locale '" + locale + "', got " + e);
+  }
+}
+
+var badLocales =
+  [
+   "en-u-foo-U-foo",
+   "en-tester-Tester",
+   "en-tesTER-TESter",
+   "de-DE-u-kn-true-U-kn-true",
+   "ar-u-foo-q-bar-u-baz",
+   "ar-z-moo-u-foo-q-bar-z-eit-u-baz",
+  ];
+
+for (var locale of badLocales)
+  checkInvalidLocale(locale);
+
+// Fully-privateuse locales are rejected.
+for (var locale of badLocales)
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("x-" + locale), RangeError);
+
+// Locales with trailing privateuse also okay.
+for (var locale of badLocales)
+{
+  new Intl.NumberFormat("en-x-" + locale).format(5);
+  new Intl.NumberFormat("en-u-foo-x-u-" + locale).format(5);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/format-as-code-or-name.js b/js/src/tests/non262/Intl/NumberFormat/format-as-code-or-name.js
new file mode 100644
index 0000000000..ba257ecd71
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/format-as-code-or-name.js
@@ -0,0 +1,75 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 1093421;
+var summary =
+  "new Intl.NumberFormat(..., { style: 'currency', currency: '...', " +
+  "currencyDisplay: 'name' or 'code' }) should have behavior other than " +
+  "throwing";
+
+print(BUGNUMBER + ": " + summary);
+
+//-----------------------------------------------------------------------------
+
+// Test that currencyDisplay: "code" behaves correctly and doesn't throw.
+
+var usdCodeOptions =
+  {
+    style: "currency",
+    currency: "USD",
+    currencyDisplay: "code",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var usDollarsCode = new Intl.NumberFormat("en-US", usdCodeOptions);
+assertEq(/USD/.test(usDollarsCode.format(25)), true);
+
+// ISO 4217 currency codes are formed from an ISO 3166-1 alpha-2 country code
+// followed by a third letter.  ISO 3166 guarantees that no country code
+// starting with "X" will ever be assigned.  Stepping carefully around a few
+// 4217-designated special "currencies", XQQ will never have a representation.
+// Thus, yes: this really is specified to work, as unrecognized or unsupported
+// codes pass into the string unmodified.
+var xqqCodeOptions =
+  {
+    style: "currency",
+    currency: "XQQ",
+    currencyDisplay: "code",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var xqqMoneyCode = new Intl.NumberFormat("en-US", xqqCodeOptions);
+assertEq(/XQQ/.test(xqqMoneyCode.format(25)), true);
+
+// Test that currencyDisplay: "name" behaves without throwing.  (Unlike the two
+// above tests, the results here aren't guaranteed as the name is
+// implementation-defined.)
+var usdNameOptions =
+  {
+    style: "currency",
+    currency: "USD",
+    currencyDisplay: "name",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var usDollarsName = new Intl.NumberFormat("en-US", usdNameOptions);
+assertEq(usDollarsName.format(25), "25 US dollars");
+
+// But if the implementation doesn't recognize the currency, the provided code
+// is used in place of a proper name, unmolested.
+var xqqNameOptions =
+  {
+    style: "currency",
+    currency: "XQQ",
+    currencyDisplay: "name",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var xqqMoneyName = new Intl.NumberFormat("en-US", xqqNameOptions);
+assertEq(/XQQ/.test(xqqMoneyName.format(25)), true);
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/format-string.js b/js/src/tests/non262/Intl/NumberFormat/format-string.js
new file mode 100644
index 0000000000..88b11008d9
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/format-string.js
@@ -0,0 +1,150 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+function groupByThree(s) {
+  return String(s).split("").reduceRight((acc, x) => x + (acc.match(/^\d{3}/) ? "," : "") + acc, "");
+}
+
+const tests = [
+  {value: "", expected: "0"},
+  {value: "0", expected: "0"},
+  {value: "+0", expected: "0"},
+  {value: "-0", expected: "-0"},
+
+  {value: "Infinity", expected: "∞"},
+  {value: "+Infinity", expected: "∞"},
+  {value: "-Infinity", expected: "-∞"},
+
+  {value: "NaN", expected: "NaN"},
+  {value: "invalid", expected: "NaN"},
+
+  // Integer 1 with and without fractional/exponent part.
+  {value: "1", expected: "1"},
+  {value: "1.", expected: "1"},
+  {value: "1.0", expected: "1"},
+  {value: "1.00", expected: "1"},
+  {value: "1e0", expected: "1"},
+  {value: "1e+0", expected: "1"},
+  {value: "1e-0", expected: "1"},
+
+  // Leading zeros.
+  {value: "01", expected: "1"},
+  {value: "01.", expected: "1"},
+  {value: "01.0", expected: "1"},
+  {value: "01.00", expected: "1"},
+  {value: "01e0", expected: "1"},
+  {value: "01e+0", expected: "1"},
+  {value: "01e-0", expected: "1"},
+
+  // Large values.
+  {value: "1e300", expected: "1" + ",000".repeat(100)},
+  {value: "1e3000", expected: "1" + ",000".repeat(1000)},
+  {value: "9007199254740991", expected: "9,007,199,254,740,991"},
+  {value: "9007199254740992", expected: "9,007,199,254,740,992"},
+  {value: "9007199254740993", expected: "9,007,199,254,740,993"},
+
+  {value: "-1e300", expected: "-1" + ",000".repeat(100)},
+  {value: "-1e3000", expected: "-1" + ",000".repeat(1000)},
+  {value: "-9007199254740991", expected: "-9,007,199,254,740,991"},
+  {value: "-9007199254740992", expected: "-9,007,199,254,740,992"},
+  {value: "-9007199254740993", expected: "-9,007,199,254,740,993"},
+
+  // Small values.
+  {value: "0.10000000000000000001", expected: "0.10000000000000000001"},
+  {value: "0.00000000000000000001", expected: "0.00000000000000000001"},
+  {value: "1e-20", expected: "0.00000000000000000001"},
+  {value: "1e-30", expected: "0"},
+
+  {value: "-0.10000000000000000001", expected: "-0.10000000000000000001"},
+  {value: "-0.00000000000000000001", expected: "-0.00000000000000000001"},
+  {value: "-1e-20", expected: "-0.00000000000000000001"},
+  {value: "-1e-30", expected: "-0"},
+
+  // Non-standard exponent notation.
+  {value: ".001e-2", expected: "0.00001"},
+  {value: "123.001e-2", expected: "1.23001"},
+  {value: "1000e-2", expected: "10"},
+  {value: "1000e+2", expected: "100,000"},
+  {value: "1000e-0", expected: "1,000"},
+
+  // Non-decimal strings.
+  {value: "0b101", expected: "5"},
+  {value: "0o377", expected: "255"},
+  {value: "0xdeadBEEF", expected: "3,735,928,559"},
+  {value: "0B0011", expected: "3"},
+  {value: "0O0777", expected: "511"},
+  {value: "0X0ABC", expected: "2,748"},
+  {value: "0b" + "1".repeat(1000), expected: groupByThree((2n ** 1000n) - 1n)},
+  {value: "0o1" + "7".repeat(333), expected: groupByThree((2n ** 1000n) - 1n)},
+  {value: "0x" + "f".repeat(250), expected: groupByThree((2n ** 1000n) - 1n)},
+
+  // Non-decimal strings don't accept a sign.
+  {value: "+0xbad", expected: "NaN"},
+  {value: "-0xbad", expected: "NaN"},
+];
+
+// https://tc39.es/ecma262/#prod-StrWhiteSpaceChar
+const strWhiteSpaceChar = [
+  "",
+
+  // https://tc39.es/ecma262/#sec-white-space
+  "\t", "\v", "\f", " ", "\u00A0", "\uFEFF",
+  "\u1680", "\u2000", "\u2001", "\u2002", "\u2003", "\u2004", "\u2005", "\u2006",
+  "\u2007", "\u2008", "\u2009", "\u200A", "\u202F", "\u205F", "\u3000",
+
+  // https://tc39.es/ecma262/#sec-line-terminators
+  "\n", "\r", "\u2028", "\u2029",
+];
+
+let nf = new Intl.NumberFormat("en", {maximumFractionDigits: 20});
+for (let {value, expected} of tests) {
+  for (let ws of strWhiteSpaceChar) {
+    assertEq(nf.format(ws + value), expected);
+    assertEq(nf.format(value + ws), expected);
+    assertEq(nf.format(ws + value + ws), expected);
+  }
+}
+
+// The specification doesn't impose any limits for the exponent, but we throw
+// an error if the exponent is too large.
+{
+  let nf = new Intl.NumberFormat("en", {useGrouping: false});
+  for (let value of [
+    // ICU limit is 999'999'999 (exclusive).
+    ".1e-999999999",
+    ".1e+999999999",
+
+    // We limit positive exponents to 9'999'999 (inclusive).
+    "1e+9999999",
+    "1e+99999999",
+
+    // Int32 overflow when computing the exponent.
+    ".1e-2147483649",
+    ".1e-2147483648",
+    ".1e-2147483647",
+    ".1e+2147483647",
+    ".1e+2147483648",
+    ".1e+2147483649",
+  ]) {
+    assertThrowsInstanceOf(() => nf.format(value), RangeError);
+  }
+
+  // We allow up to ±9'999'999.
+  assertEq(nf.format(".1e-9999999"), "0");
+  assertEq(nf.format(".1e+9999999"), "1" + "0".repeat(9_999_999 - 1));
+
+  // Negative exponents are even valid up to -999'999'998
+  assertEq(nf.format(".1e-999999998"), "0");
+}
+
+// Combine extreme values with other rounding modes.
+{
+  let nf = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 20,
+    roundingMode: "ceil",
+    roundingIncrement: 5000,
+  });
+  assertEq(nf.format(".1e-999999998"), "0.00000000000000005000");
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/format.js b/js/src/tests/non262/Intl/NumberFormat/format.js
new file mode 100644
index 0000000000..db35251b20
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/format.js
@@ -0,0 +1,55 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Tests the format function with a diverse set of locales and options.
+
+var format;
+
+// Locale en-US; default options.
+format = new Intl.NumberFormat("en-us");
+assertEq(format.format(0), "0");
+assertEq(format.format(-1), "-1");
+assertEq(format.format(123456789.123456789), "123,456,789.123");
+
+// Locale en-US; currency USD.
+// The US dollar uses two fractional digits, and negative values are commonly
+// parenthesized.
+format = new Intl.NumberFormat("en-us", {style: "currency", currency: "USD"});
+assertEq(format.format(0), "$0.00");
+assertEq(format.format(-1), "-$1.00");
+assertEq(format.format(123456789.123456789), "$123,456,789.12");
+
+// Locale ja-JP; currency JPY.
+// The Japanese yen has no subunit in real life.
+format = new Intl.NumberFormat("ja-jp", {style: "currency", currency: "JPY"});
+assertEq(format.format(0), "￥0");
+assertEq(format.format(-1), "-￥1");
+assertEq(format.format(123456789.123456789), "￥123,456,789");
+
+// Locale ar-JO; currency JOD.
+// The Jordanian Dinar divides into 1000 fils. Jordan uses (real) Arabic digits.
+format = new Intl.NumberFormat("ar-jo", {style: "currency", currency: "JOD"});
+assertEq(format.format(0), "\u{200F}٠٫٠٠٠ د.أ.\u{200F}");
+assertEq(format.format(-1), "\u{061C}-\u{200F}١٫٠٠٠ د.أ.\u{200F}");
+assertEq(format.format(123456789.123456789), "\u{200F}١٢٣٬٤٥٦٬٧٨٩٫١٢٣ د.أ.\u{200F}");
+
+// Locale th-TH; Thai digits, percent, two significant digits.
+format = new Intl.NumberFormat("th-th-u-nu-thai",
+                               {style: "percent",
+                                minimumSignificantDigits: 2,
+                                maximumSignificantDigits: 2});
+assertEq(format.format(0), "๐.๐%");
+assertEq(format.format(-0.01), "-๑.๐%");
+assertEq(format.format(1.10), "๑๑๐%");
+
+
+// Test the .name property of the "format" getter.
+var desc = Object.getOwnPropertyDescriptor(Intl.NumberFormat.prototype, "format");
+assertEq(desc !== undefined, true);
+assertEq(typeof desc.get, "function");
+assertEq(desc.get.name, "get format");
+
+
+reportCompare(0, 0, 'ok');
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRange-BigInt.js b/js/src/tests/non262/Intl/NumberFormat/formatRange-BigInt.js
new file mode 100644
index 0000000000..36ccdf59e3
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRange-BigInt.js
@@ -0,0 +1,150 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+// Int64-BigInts which can be exactly represented as doubles receive a fast-path.
+
+const tests = {
+  "en": {
+    options: {},
+    ranges: [
+      // BigInt around Number.MIN_SAFE_INTEGER.
+      {
+        start: -0x20000000000001n,
+        end: -0x20000000000000n,
+        result: "-9,007,199,254,740,993 – -9,007,199,254,740,992",
+      },
+      {
+        start: -0x20000000000000n,
+        end: -0x20000000000000n,
+        result: "~-9,007,199,254,740,992",
+      },
+      {
+        start: -0x20000000000000n,
+        end: -0x1fffffffffffffn,
+        result: "-9,007,199,254,740,992 – -9,007,199,254,740,991",
+      },
+      {
+        start: -0x1fffffffffffffn,
+        end: -0x1fffffffffffffn,
+        result: "~-9,007,199,254,740,991",
+      },
+      {
+        start: -0x1fffffffffffffn,
+        end: -0x1ffffffffffffen,
+        result: "-9,007,199,254,740,991 – -9,007,199,254,740,990",
+      },
+      {
+        start: -0x1ffffffffffffen,
+        end: -0x1ffffffffffffen,
+        result: "~-9,007,199,254,740,990",
+      },
+
+      // BigInt around Number.MAX_SAFE_INTEGER.
+      {
+        start: 0x1ffffffffffffen,
+        end: 0x1ffffffffffffen,
+        result: "~9,007,199,254,740,990",
+      },
+      {
+        start: 0x1ffffffffffffen,
+        end: 0x1fffffffffffffn,
+        result: "9,007,199,254,740,990–9,007,199,254,740,991",
+      },
+      {
+        start: 0x1fffffffffffffn,
+        end: 0x1fffffffffffffn,
+        result: "~9,007,199,254,740,991",
+      },
+      {
+        start: 0x1fffffffffffffn,
+        end: 0x20000000000000n,
+        result: "9,007,199,254,740,991–9,007,199,254,740,992",
+      },
+      {
+        start: 0x20000000000000n,
+        end: 0x20000000000000n,
+        result: "~9,007,199,254,740,992",
+      },
+      {
+        start: 0x20000000000000n,
+        end: 0x20000000000001n,
+        result: "9,007,199,254,740,992–9,007,199,254,740,993",
+      },
+
+      // BigInt around INT64_MIN.
+      {
+        start: -0x8000000000000002n,
+        end: -0x8000000000000001n,
+        result: "-9,223,372,036,854,775,810 – -9,223,372,036,854,775,809",
+      },
+      {
+        start: -0x8000000000000001n,
+        end: -0x8000000000000001n,
+        result: "~-9,223,372,036,854,775,809",
+      },
+      {
+        start: -0x8000000000000001n,
+        end: -0x8000000000000000n,
+        result: "-9,223,372,036,854,775,809 – -9,223,372,036,854,775,808",
+      },
+      {
+        start: -0x8000000000000000n,
+        end: -0x8000000000000000n,
+        result: "~-9,223,372,036,854,775,808",
+      },
+      {
+        start: -0x8000000000000000n,
+        end: -0x7fffffffffffffffn,
+        result: "-9,223,372,036,854,775,808 – -9,223,372,036,854,775,807",
+      },
+      {
+        start: -0x7fffffffffffffffn,
+        end: -0x7fffffffffffffffn,
+        result: "~-9,223,372,036,854,775,807",
+      },
+
+      // BigInt around INT64_MAX.
+      {
+        start: 0x7ffffffffffffffen,
+        end: 0x7ffffffffffffffen,
+        result: "~9,223,372,036,854,775,806",
+      },
+      {
+        start: 0x7ffffffffffffffen,
+        end: 0x7fffffffffffffffn,
+        result: "9,223,372,036,854,775,806–9,223,372,036,854,775,807",
+      },
+      {
+        start: 0x7fffffffffffffffn,
+        end: 0x7fffffffffffffffn,
+        result: "~9,223,372,036,854,775,807",
+      },
+      {
+        start: 0x7fffffffffffffffn,
+        end: 0x8000000000000000n,
+        result: "9,223,372,036,854,775,807–9,223,372,036,854,775,808",
+      },
+      {
+        start: 0x8000000000000000n,
+        end: 0x8000000000000000n,
+        result: "~9,223,372,036,854,775,808",
+      },
+      {
+        start: 0x8000000000000000n,
+        end: 0x8000000000000001n,
+        result: "9,223,372,036,854,775,808–9,223,372,036,854,775,809",
+      },
+    ],
+  },
+};
+
+for (let [locale, {options, ranges}] of Object.entries(tests)) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let {start, end, result} of ranges) {
+    assertEq(nf.formatRange(start, end), result, `${start}-${end}`);
+    assertEq(nf.formatRangeToParts(start, end).reduce((acc, part) => acc + part.value, ""),
+             result, `${start}-${end}`);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRange.js b/js/src/tests/non262/Intl/NumberFormat/formatRange.js
new file mode 100644
index 0000000000..da5a940ca8
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRange.js
@@ -0,0 +1,296 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+// String representation for Number.MAX_VALUE.
+const en_Number_MAX_VALUE = "179,769,313,486,231,570" + ",000".repeat(97);
+const de_Number_MAX_VALUE = en_Number_MAX_VALUE.replaceAll(",", ".");
+const fr_Number_MAX_VALUE = en_Number_MAX_VALUE.replaceAll(",", " ");
+
+const tests = {
+  "en": {
+    options: {},
+    ranges: [
+      // Values around zero.
+      {start: 0, end: 0, result: "~0"},
+      {start: 0, end: -0, result: "0–-0"},
+      {start: -0, end: 0, result: "-0 – 0"},
+      {start: -0, end: 0.1e-3, result: "-0 – 0"},
+      {start: -0, end: "0.1e-3", result: "-0 – 0"},
+      {start: "-0", end: 0.1e-3, result: "-0 – 0"},
+      {start: -0, end: -0, result: "~-0"},
+      {start: -0, end: -0.1, result: "-0 – -0.1"},
+
+      // Values starting at negative infinity.
+      {start: -Infinity, end: -Infinity, result: "~-∞"},
+      {start: -Infinity, end: -0, result: "-∞ – -0"},
+      {start: -Infinity, end: +0, result: "-∞ – 0"},
+      {start: -Infinity, end: +Infinity, result: "-∞ – ∞"},
+
+      // Values ending at negative infinity.
+      {start: -Number.MAX_VALUE, end: -Infinity, result: "-" + en_Number_MAX_VALUE + " – -∞"},
+      {start: -0, end: -Infinity, result: "-0 – -∞"},
+      {start: 0, end: -Infinity, result: "0–-∞"},
+      {start: Number.MAX_VALUE, end: -Infinity, result: en_Number_MAX_VALUE + "–-∞"},
+
+      // Values starting at positive infinity.
+      {start: Infinity, end: Number.MAX_VALUE, result: "∞–" + en_Number_MAX_VALUE},
+      {start: Infinity, end: 0, result: "∞–0"},
+      {start: Infinity, end: -0, result: "∞–-0"},
+      {start: Infinity, end: -Number.MAX_VALUE, result: "∞–-" + en_Number_MAX_VALUE},
+      {start: Infinity, end: -Infinity, result: "∞–-∞"},
+
+      // Values ending at positive infinity.
+      {start: Infinity, end: Infinity, result: "~∞"},
+
+      // Non-special cases.
+      {start: 1, end: 100, result: "1–100"},
+      {start: -100, end: 100, result: "-100 – 100"},
+      {start: -1000, end: -100, result: "-1,000 – -100"},
+      {start: Math.PI, end: 123_456.789, result: "3.142–123,456.789"},
+      {start: -Math.PI, end: Math.E, result: "-3.142 – 2.718"},
+      {
+        start: Number.MAX_SAFE_INTEGER,
+        end: 9007199254740993,
+        result: "9,007,199,254,740,991–9,007,199,254,740,992",
+      },
+      {
+        start: Number.MAX_SAFE_INTEGER,
+        end: "9007199254740993",
+        result: "9,007,199,254,740,991–9,007,199,254,740,993",
+      },
+
+      // Start value is larger than end value.
+      {start: -0, end: -0.1, result: "-0 – -0.1"},
+      {start: -0, end: -Number.MAX_VALUE, result: "-0 – -" + en_Number_MAX_VALUE},
+      {start: 1, end: 0, result: "1–0"},
+      {start: 0, end: -1, result: "0–-1"},
+      {start: 1, end: -1, result: "1–-1"},
+      {start: -1, end: -2, result: "-1 – -2"},
+      {start: "10e2", end: "1e-3", result: "1,000–0.001"},
+      {start: "0x100", end: "1e1", result: "256–10"},
+      {start: ".1e-999999", end: ".01e-999999", result: "~0"},
+      {start: ".1e99999", end: "0", result: "100" + ",000".repeat(33332) + "–0"},
+      // Number.MAX_VALUE is 1.7976931348623157e+308.
+      {
+        start: "1.7976931348623158e+308",
+        end: Number.MAX_VALUE,
+        result: "179,769,313,486,231,580" + ",000".repeat(97) + "–" + en_Number_MAX_VALUE,
+      },
+      // Number.MIN_VALUE is 5e-324.
+      {start: "6e-324", end: Number.MIN_VALUE, result: "~0"},
+    ],
+  },
+  "de": {
+    options: {style: "currency", currency: "EUR"},
+    ranges: [
+      // Values around zero.
+      {start: 0, end: 0, result: "≈0,00 €"},
+      {start: 0, end: -0, result: "0,00 € – -0,00 €"},
+      {start: -0, end: 0, result: "-0,00 € – 0,00 €"},
+      {start: -0, end: 0.1e-3, result: "-0,00 € – 0,00 €"},
+      {start: -0, end: "0.1e-3", result: "-0,00 € – 0,00 €"},
+      {start: "-0", end: 0.1e-3, result: "-0,00 € – 0,00 €"},
+      {start: -0, end: -0, result: "≈-0,00 €"},
+      {start: -0, end: -0.1, result: "-0,00–0,10 €"},
+
+      // Values starting at negative infinity.
+      {start: -Infinity, end: -Infinity, result: "≈-∞ €"},
+      {start: -Infinity, end: -0, result: "-∞–0,00 €"},
+      {start: -Infinity, end: +0, result: "-∞ € – 0,00 €"},
+      {start: -Infinity, end: +Infinity, result: "-∞ € – ∞ €"},
+
+      // Values ending at negative infinity.
+      {start: -Number.MAX_VALUE, end: -Infinity, result: "-" + de_Number_MAX_VALUE + ",00–∞ €"},
+      {start: -0, end: -Infinity, result: "-0,00–∞ €"},
+      {start: 0, end: -Infinity, result: "0,00 € – -∞ €"},
+      {start: Number.MAX_VALUE, end: -Infinity, result: de_Number_MAX_VALUE + ",00 € – -∞ €"},
+
+      // Values starting at positive infinity.
+      {start: Infinity, end: Number.MAX_VALUE, result: "∞–" + de_Number_MAX_VALUE + ",00 €"},
+      {start: Infinity, end: 0, result: "∞–0,00 €"},
+      {start: Infinity, end: -0, result: "∞ € – -0,00 €"},
+      {start: Infinity, end: -Number.MAX_VALUE, result: "∞ € – -" + de_Number_MAX_VALUE + ",00 €"},
+      {start: Infinity, end: -Infinity, result: "∞ € – -∞ €"},
+
+      // Values ending at positive infinity.
+      {start: Infinity, end: Infinity, result: "≈∞ €"},
+
+      // Non-special cases.
+      {start: 1, end: 100, result: "1,00–100,00 €"},
+      {start: -100, end: 100, result: "-100,00 € – 100,00 €"},
+      {start: -1000, end: -100, result: "-1.000,00–100,00 €"},
+      {start: Math.PI, end: 123_456.789, result: "3,14–123.456,79 €"},
+      {start: -Math.PI, end: Math.E, result: "-3,14 € – 2,72 €"},
+      {
+        start: Number.MAX_SAFE_INTEGER,
+        end: 9007199254740993,
+        result: "9.007.199.254.740.991,00–9.007.199.254.740.992,00 €",
+      },
+      {
+        start: Number.MAX_SAFE_INTEGER,
+        end: "9007199254740993",
+        result: "9.007.199.254.740.991,00–9.007.199.254.740.993,00 €",
+      },
+
+      // Start value is larger than end value.
+      {start: -0, end: -0.1, result: "-0,00–0,10 €"},
+      {start: -0, end: -Number.MAX_VALUE, result: "-0,00–" + de_Number_MAX_VALUE + ",00 €"},
+      {start: 1, end: 0, result: "1,00–0,00 €"},
+      {start: 0, end: -1, result: "0,00 € – -1,00 €"},
+      {start: 1, end: -1, result: "1,00 € – -1,00 €"},
+      {start: -1, end: -2, result: "-1,00–2,00 €"},
+      {start: "10e2", end: "1e-3", result: "1.000,00–0,00 €"},
+      {start: "0x100", end: "1e1", result: "256,00–10,00 €"},
+      {start: ".1e-999999", end: ".01e-999999", result: "≈0,00 €"},
+      {start: ".1e99999", end: "0", result: "100" + ".000".repeat(33332) + ",00–0,00 €"},
+      // Number.MAX_VALUE is 1.7976931348623157e+308.
+      {
+        start: "1.7976931348623158e+308",
+        end: Number.MAX_VALUE,
+        result: "179.769.313.486.231.580" + ".000".repeat(97) + ",00–" + de_Number_MAX_VALUE + ",00 €",
+      },
+      // Number.MIN_VALUE is 5e-324.
+      {start: "6e-324", end: Number.MIN_VALUE, result: "≈0,00 €"},
+    ],
+  },
+  "fr": {
+    options: {style: "unit", unit: "meter"},
+    ranges: [
+      // Values around zero.
+      {start: 0, end: 0, result: "≃0 m"},
+      {start: -0, end: 0, result: "-0 – 0 m"},
+      {start: -0, end: 0, result: "-0 – 0 m"},
+      {start: -0, end: 0.1e-3, result: "-0 – 0 m"},
+      {start: -0, end: "0.1e-3", result: "-0 – 0 m"},
+      {start: "-0", end: 0.1e-3, result: "-0 – 0 m"},
+      {start: -0, end: -0, result: "≃-0 m"},
+      {start: -0, end: -0.1, result: "-0 – -0,1 m"},
+
+      // Values starting at negative infinity.
+      {start: -Infinity, end: -Infinity, result: "≃-∞ m"},
+      {start: -Infinity, end: -0, result: "-∞ – -0 m"},
+      {start: -Infinity, end: +0, result: "-∞ – 0 m"},
+      {start: -Infinity, end: +Infinity, result: "-∞ – ∞ m"},
+
+      // Values ending at negative infinity.
+      {start: -Number.MAX_VALUE, end: -Infinity, result: "-" + fr_Number_MAX_VALUE + " – -∞ m"},
+      {start: -0, end: -Infinity, result: "-0 – -∞ m"},
+      {start: 0, end: -Infinity, result: "0–-∞ m"},
+      {start: Number.MAX_VALUE, end: -Infinity, result: fr_Number_MAX_VALUE + "–-∞ m"},
+
+      // Values starting at positive infinity.
+      {start: Infinity, end: Number.MAX_VALUE, result: "∞–" + fr_Number_MAX_VALUE + " m"},
+      {start: Infinity, end: 0, result: "∞–0 m"},
+      {start: Infinity, end: -0, result: "∞–-0 m"},
+      {start: Infinity, end: -Number.MAX_VALUE, result: "∞–-" + fr_Number_MAX_VALUE + " m"},
+      {start: Infinity, end: -Infinity, result: "∞–-∞ m"},
+
+      // Values ending at positive infinity.
+      {start: Infinity, end: Infinity, result: "≃∞ m"},
+
+      // Non-special cases.
+      {start: 1, end: 100, result: "1–100 m"},
+      {start: -100, end: 100, result: "-100 – 100 m"},
+      {start: -1000, end: -100, result: "-1 000 – -100 m"},
+      {start: Math.PI, end: 123_456.789, result: "3,142–123 456,789 m"},
+      {start: -Math.PI, end: Math.E, result: "-3,142 – 2,718 m"},
+      {
+        start: Number.MAX_SAFE_INTEGER,
+        end: 9007199254740993,
+        result: "9 007 199 254 740 991–9 007 199 254 740 992 m",
+      },
+      {
+        start: Number.MAX_SAFE_INTEGER,
+        end: "9007199254740993",
+        result: "9 007 199 254 740 991–9 007 199 254 740 993 m",
+      },
+
+      // Start value is larger than end value.
+      {start: -0, end: -0.1, result: "-0 – -0,1 m"},
+      {start: -0, end: -Number.MAX_VALUE, result: "-0 – -" + fr_Number_MAX_VALUE + " m"},
+      {start: 1, end: 0, result: "1–0 m"},
+      {start: 0, end: -1, result: "0–-1 m"},
+      {start: 1, end: -1, result: "1–-1 m"},
+      {start: -1, end: -2, result: "-1 – -2 m"},
+      {start: "10e2", end: "1e-3", result: "1 000–0,001 m"},
+      {start: "0x100", end: "1e1", result: "256–10 m"},
+      {start: ".1e-999999", end: ".01e-999999", result: "≃0 m"},
+      {start: ".1e99999", end: "0", result: "100" + " 000".repeat(33332) + "–0 m"},
+      // Number.MAX_VALUE is 1.7976931348623157e+308.
+      {
+        start: "1.7976931348623158e+308",
+        end: Number.MAX_VALUE,
+        result: "179 769 313 486 231 580" + " 000".repeat(97) + "–" + fr_Number_MAX_VALUE + " m",
+      },
+      // Number.MIN_VALUE is 5e-324.
+      {start: "6e-324", end: Number.MIN_VALUE, result: "≃0 m"},
+    ],
+  },
+  // Non-ASCII digits.
+  "ar": {
+    options: {},
+    ranges: [
+      {start: -2, end: -1, result: "؜-٢–١"},
+      {start: -1, end: -1, result: "~؜-١"},
+      {start: -1, end: 0, result: "؜-١ – ٠"},
+      {start: 0, end: 0, result: "~٠"},
+      {start: 0, end: 1, result: "٠–١"},
+      {start: 1, end: 1, result: "~١"},
+      {start: 1, end: 2, result: "١–٢"},
+    ],
+  },
+  "th-u-nu-thai": {
+    options: {},
+    ranges: [
+      {start: -2, end: -1, result: "-๒ - -๑"},
+      {start: -1, end: -1, result: "~-๑"},
+      {start: -1, end: 0, result: "-๑ - ๐"},
+      {start: 0, end: 0, result: "~๐"},
+      {start: 0, end: 1, result: "๐-๑"},
+      {start: 1, end: 1, result: "~๑"},
+      {start: 1, end: 2, result: "๑-๒"},
+    ],
+  },
+  // Approximation sign may consist of multiple characters.
+  "no": {
+    options: {},
+    ranges: [
+      {start: 1, end: 1, result: "ca.1"},
+    ],
+  },
+  // Approximation sign can be a word.
+  "ja": {
+    options: {},
+    ranges: [
+      {start: 1, end: 1, result: "約1"},
+    ],
+  },
+};
+
+for (let [locale, {options, ranges}] of Object.entries(tests)) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let {start, end, result} of ranges) {
+    assertEq(nf.formatRange(start, end), result, `${start}-${end}`);
+    assertEq(nf.formatRangeToParts(start, end).reduce((acc, part) => acc + part.value, ""),
+             result, `${start}-${end}`);
+  }
+}
+
+// Throws an error if either value is NaN.
+{
+  const errorTests = [
+    {start: NaN, end: NaN},
+    {start: 0, end: NaN},
+    {start: NaN, end: 0},
+    {start: Infinity, end: NaN},
+    {start: NaN, end: Infinity},
+  ];
+
+  let nf = new Intl.NumberFormat("en");
+  for (let {start, end} of errorTests) {
+    assertThrowsInstanceOf(() => nf.formatRange(start, end), RangeError);
+    assertThrowsInstanceOf(() => nf.formatRangeToParts(start, end), RangeError);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-compact.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-compact.js
new file mode 100644
index 0000000000..b3ee5aedf3
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-compact.js
@@ -0,0 +1,34 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+if (typeof getAvailableLocalesOf === "undefined") {
+  var getAvailableLocalesOf = SpecialPowers.Cu.getJSTestingFunctions().getAvailableLocalesOf;
+}
+
+const numbers = [
+  0, 1, 2, 5, 10, 100, 1000, 10_000, 100_000, 1_000_000,
+  0.1, 0.2, 0.5, 1.5,
+  -0, -1, -2, -5,
+  Infinity, -Infinity,
+];
+
+const options = {notation: "compact"};
+
+// List of known approximately sign in CLDR 40.
+const approximatelySigns = [
+  "~", "∼", "≈", "≃", "ca.", "約", "dáàṣì", "dáàshì",
+];
+
+// Iterate over all locales and ensure we find exactly one approximately sign.
+for (let locale of getAvailableLocalesOf("NumberFormat").sort()) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let number of numbers) {
+    let parts = nf.formatRangeToParts(number, number);
+    let approx = parts.filter(part => part.type === "approximatelySign");
+
+    assertEq(approx.length, 1);
+    assertEq(approximatelySigns.some(approxSign => approx[0].value.includes(approxSign)), true);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-currency.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-currency.js
new file mode 100644
index 0000000000..72722b3b18
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-currency.js
@@ -0,0 +1,34 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+if (typeof getAvailableLocalesOf === "undefined") {
+  var getAvailableLocalesOf = SpecialPowers.Cu.getJSTestingFunctions().getAvailableLocalesOf;
+}
+
+const numbers = [
+  0, 1, 2, 5, 10, 100, 1000, 10_000, 100_000, 1_000_000,
+  0.1, 0.2, 0.5, 1.5,
+  -0, -1, -2, -5,
+  Infinity, -Infinity,
+];
+
+const options = {style: "currency", currency: "EUR"};
+
+// List of known approximately sign in CLDR 40.
+const approximatelySigns = [
+  "~", "∼", "≈", "≃", "ca.", "約", "dáàṣì", "dáàshì",
+];
+
+// Iterate over all locales and ensure we find exactly one approximately sign.
+for (let locale of getAvailableLocalesOf("NumberFormat").sort()) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let number of numbers) {
+    let parts = nf.formatRangeToParts(number, number);
+    let approx = parts.filter(part => part.type === "approximatelySign");
+
+    assertEq(approx.length, 1);
+    assertEq(approximatelySigns.some(approxSign => approx[0].value.includes(approxSign)), true);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-percent.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-percent.js
new file mode 100644
index 0000000000..f93ae25de8
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-percent.js
@@ -0,0 +1,34 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+if (typeof getAvailableLocalesOf === "undefined") {
+  var getAvailableLocalesOf = SpecialPowers.Cu.getJSTestingFunctions().getAvailableLocalesOf;
+}
+
+const numbers = [
+  0, 1, 2, 5, 10, 100, 1000, 10_000, 100_000, 1_000_000,
+  0.1, 0.2, 0.5, 1.5,
+  -0, -1, -2, -5,
+  Infinity, -Infinity,
+];
+
+const options = {style: "percent"};
+
+// List of known approximately sign in CLDR 40.
+const approximatelySigns = [
+  "~", "∼", "≈", "≃", "ca.", "約", "dáàṣì", "dáàshì",
+];
+
+// Iterate over all locales and ensure we find exactly one approximately sign.
+for (let locale of getAvailableLocalesOf("NumberFormat").sort()) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let number of numbers) {
+    let parts = nf.formatRangeToParts(number, number);
+    let approx = parts.filter(part => part.type === "approximatelySign");
+
+    assertEq(approx.length, 1);
+    assertEq(approximatelySigns.some(approxSign => approx[0].value.includes(approxSign)), true);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-signDisplay.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-signDisplay.js
new file mode 100644
index 0000000000..197f6f9f0d
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-signDisplay.js
@@ -0,0 +1,34 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+if (typeof getAvailableLocalesOf === "undefined") {
+  var getAvailableLocalesOf = SpecialPowers.Cu.getJSTestingFunctions().getAvailableLocalesOf;
+}
+
+const numbers = [
+  0, 1, 2, 5, 10, 100, 1000, 10_000, 100_000, 1_000_000,
+  0.1, 0.2, 0.5, 1.5,
+  -0, -1, -2, -5,
+  Infinity, -Infinity,
+];
+
+const options = {signDisplay: "always"};
+
+// List of known approximately sign in CLDR 40.
+const approximatelySigns = [
+  "~", "∼", "≈", "≃", "ca.", "約", "dáàṣì", "dáàshì",
+];
+
+// Iterate over all locales and ensure we find exactly one approximately sign.
+for (let locale of getAvailableLocalesOf("NumberFormat").sort()) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let number of numbers) {
+    let parts = nf.formatRangeToParts(number, number);
+    let approx = parts.filter(part => part.type === "approximatelySign");
+
+    assertEq(approx.length, 1);
+    assertEq(approximatelySigns.some(approxSign => approx[0].value.includes(approxSign)), true);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-unit.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-unit.js
new file mode 100644
index 0000000000..51507e57df
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign-unit.js
@@ -0,0 +1,41 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+if (typeof getAvailableLocalesOf === "undefined") {
+  var getAvailableLocalesOf = SpecialPowers.Cu.getJSTestingFunctions().getAvailableLocalesOf;
+}
+
+const numbers = [
+  0, 1, 2, 5, 10, 100, 1000, 10_000, 100_000, 1_000_000,
+  0.1, 0.2, 0.5, 1.5,
+  -0, -1, -2, -5,
+  Infinity, -Infinity,
+];
+
+const options = {style: "unit", unit: "meter"};
+
+// List of known approximately sign in CLDR 40.
+const approximatelySigns = [
+  "~", "∼", "≈", "≃", "ca.", "約", "dáàṣì", "dáàshì",
+];
+
+// Iterate over all locales and ensure we find exactly one approximately sign.
+for (let locale of getAvailableLocalesOf("NumberFormat").sort()) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let number of numbers) {
+    let parts = nf.formatRangeToParts(number, number);
+    let approx = parts.filter(part => part.type === "approximatelySign");
+
+    // Known failure case.
+    // - https://github.com/tc39/proposal-intl-numberformat-v3/issues/64
+    // - https://unicode-org.atlassian.net/browse/CLDR-14918
+    if (approx.length === 0 && new Intl.Locale(locale).language === "ar") {
+      continue;
+    }
+
+    assertEq(approx.length, 1);
+    assertEq(approximatelySigns.some(approxSign => approx[0].value.includes(approxSign)), true);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign.js
new file mode 100644
index 0000000000..edb63c2b00
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts-approximately-sign.js
@@ -0,0 +1,34 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+if (typeof getAvailableLocalesOf === "undefined") {
+  var getAvailableLocalesOf = SpecialPowers.Cu.getJSTestingFunctions().getAvailableLocalesOf;
+}
+
+const numbers = [
+  0, 1, 2, 5, 10, 100, 1000, 10_000, 100_000, 1_000_000,
+  0.1, 0.2, 0.5, 1.5,
+  -0, -1, -2, -5,
+  Infinity, -Infinity,
+];
+
+const options = {};
+
+// List of known approximately sign in CLDR 40.
+const approximatelySigns = [
+  "~", "∼", "≈", "≃", "ca.", "約", "dáàṣì", "dáàshì",
+];
+
+// Iterate over all locales and ensure we find exactly one approximately sign.
+for (let locale of getAvailableLocalesOf("NumberFormat").sort()) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let number of numbers) {
+    let parts = nf.formatRangeToParts(number, number);
+    let approx = parts.filter(part => part.type === "approximatelySign");
+
+    assertEq(approx.length, 1);
+    assertEq(approximatelySigns.some(approxSign => approx[0].value.includes(approxSign)), true);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts.js b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts.js
new file mode 100644
index 0000000000..264dab910c
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatRangeToParts.js
@@ -0,0 +1,174 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+const Start = NumberRangeFormatParts("startRange");
+const End = NumberRangeFormatParts("endRange");
+const Shared = NumberRangeFormatParts("shared");
+
+const tests = {
+  "en": {
+    options: {},
+    ranges: [
+      // Approximation sign present.
+      {
+        start: 0,
+        end: 0,
+        result: [Shared.Approx("~"), Shared.Integer("0")],
+      },
+      {
+        start: -0,
+        end: -0,
+        result: [Shared.Approx("~"), Shared.MinusSign("-"), Shared.Integer("0")],
+      },
+      {
+        start: -1,
+        end: -1,
+        result: [Shared.Approx("~"), Shared.MinusSign("-"), Shared.Integer("1")],
+      },
+      {
+        start: 0.5,
+        end: 0.5,
+        result: [Shared.Approx("~"), Shared.Integer("0"), Shared.Decimal("."), Shared.Fraction("5")],
+      },
+      {
+        start: Infinity,
+        end: Infinity,
+        result: [Shared.Approx("~"), Shared.Inf("∞")],
+      },
+      {
+        start: -Infinity,
+        end: -Infinity,
+        result: [Shared.Approx("~"), Shared.MinusSign("-"), Shared.Inf("∞")],
+      },
+
+      // Proper ranges.
+      {
+        start: -2,
+        end: -1,
+        result: [Start.MinusSign("-"), Start.Integer("2"), Shared.Literal(" – "), End.MinusSign("-"), End.Integer("1")],
+      },
+      {
+        start: -1,
+        end: 1,
+        result: [Start.MinusSign("-"), Start.Integer("1"), Shared.Literal(" – "), End.Integer("1")],
+      },
+      {
+        start: 1,
+        end: 2,
+        result: [Start.Integer("1"), Shared.Literal("–"), End.Integer("2")],
+      },
+    ],
+  },
+  // Non-ASCII digits.
+  "ar": {
+    options: {},
+    ranges: [
+      {
+        start: -2,
+        end: -1,
+        result: [Shared.Literal("\u061C"), Shared.MinusSign("-"), Start.Integer("٢"), Shared.Literal("–"), End.Integer("١")],
+      },
+      {
+        start: -1,
+        end: -1,
+        result: [Shared.Approx("~"), Shared.Literal("\u061C"), Shared.MinusSign("-"), Shared.Integer("١")],
+      },
+      {
+        start: -1,
+        end: 0,
+        result: [Start.Literal("\u061C"), Start.MinusSign("-"), Start.Integer("١"), Shared.Literal(" – "), End.Integer("٠")],
+      },
+      {
+        start: 0,
+        end: 0,
+        result: [Shared.Approx("~"), Shared.Integer("٠")],
+      },
+      {
+        start: 0,
+        end: 1,
+        result: [Start.Integer("٠"), Shared.Literal("–"), End.Integer("١")],
+      },
+      {
+        start: 1,
+        end: 1,
+        result: [Shared.Approx("~"), Shared.Integer("١")],
+      },
+      {
+        start: 1,
+        end: 2,
+        result: [Start.Integer("١"), Shared.Literal("–"), End.Integer("٢")],
+      },
+    ],
+  },
+  "th-u-nu-thai": {
+    options: {},
+    ranges: [
+      {
+        start: -2,
+        end: -1,
+        result: [Start.MinusSign("-"), Start.Integer("๒"), Shared.Literal(" - "), End.MinusSign("-"), End.Integer("๑")],
+      },
+      {
+        start: -1,
+        end: -1,
+        result: [Shared.Approx("~"), Shared.MinusSign("-"), Shared.Integer("๑")],
+      },
+      {
+        start: -1,
+        end: 0,
+        result: [Start.MinusSign("-"), Start.Integer("๑"), Shared.Literal(" - "), End.Integer("๐")],
+      },
+      {
+        start: 0,
+        end: 0,
+        result: [Shared.Approx("~"), Shared.Integer("๐")],
+      },
+      {
+        start: 0,
+        end: 1,
+        result: [Start.Integer("๐"), Shared.Literal("-"), End.Integer("๑")],
+      },
+      {
+        start: 1,
+        end: 1,
+        result: [Shared.Approx("~"), Shared.Integer("๑")],
+      },
+      {
+        start: 1,
+        end: 2,
+        result: [Start.Integer("๑"), Shared.Literal("-"), End.Integer("๒")],
+      },
+    ],
+  },
+  // Approximation sign may consist of multiple characters.
+  "no": {
+    options: {},
+    ranges: [
+      {
+        start: 1,
+        end: 1,
+        result: [Shared.Approx("ca."), Shared.Integer("1")],
+      },
+    ],
+  },
+  // Approximation sign can be a word.
+  "ja": {
+    options: {},
+    ranges: [
+      {
+        start: 1,
+        end: 1,
+        result: [Shared.Approx("約"), Shared.Integer("1")],
+      },
+    ],
+  },
+};
+
+for (let [locale, {options, ranges}] of Object.entries(tests)) {
+  let nf = new Intl.NumberFormat(locale, options);
+  for (let {start, end, result} of ranges) {
+    assertRangeParts(nf, start, end, result);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatToParts.js b/js/src/tests/non262/Intl/NumberFormat/formatToParts.js
new file mode 100644
index 0000000000..3ac7c3f4d3
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatToParts.js
@@ -0,0 +1,357 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/licenses/publicdomain/
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 1289882;
+var summary = "Implement Intl.NumberFormat.prototype.formatToParts";
+
+print(BUGNUMBER + ": " + summary);
+
+//-----------------------------------------------------------------------------
+
+assertEq("formatToParts" in Intl.NumberFormat(), true);
+
+// NOTE: Some of these tests exercise standard behavior (e.g. that format and
+//       formatToParts expose the same formatted string).  But much of this,
+//       like the exact-formatted-string expectations, is technically
+//       implementation-dependent.  This is necessary as a practical matter to
+//       properly test the conversion from ICU's nested-field exposure to
+//       ECMA-402's sequential-parts exposure.
+
+var {
+  Nan, Inf, Integer, Group, Decimal, Fraction,
+  MinusSign, PlusSign, PercentSign, Currency, Literal,
+} = NumberFormatParts;
+
+//-----------------------------------------------------------------------------
+
+// Test -0's partitioning now that it's not treated like +0.
+// https://github.com/tc39/ecma402/pull/232
+
+var deadSimpleFormatter = new Intl.NumberFormat("en-US");
+
+assertParts(deadSimpleFormatter, -0,
+            [MinusSign("-"), Integer("0")]);
+
+// Test behavior of a currency with code formatting.
+var usdCodeOptions =
+  {
+    style: "currency",
+    currency: "USD",
+    currencyDisplay: "code",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var usDollarsCode = new Intl.NumberFormat("en-US", usdCodeOptions);
+
+assertParts(usDollarsCode, 25,
+            [Currency("USD"), Literal("\xA0"), Integer("25")]);
+
+// ISO 4217 currency codes are formed from an ISO 3166-1 alpha-2 country code
+// followed by a third letter.  ISO 3166 guarantees that no country code
+// starting with "X" will ever be assigned.  Stepping carefully around a few
+// 4217-designated special "currencies", XQQ will never have a representation.
+// Thus, yes: this really is specified to work, as unrecognized or unsupported
+// codes pass into the string unmodified.
+var xqqCodeOptions =
+  {
+    style: "currency",
+    currency: "XQQ",
+    currencyDisplay: "code",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var xqqMoneyCode = new Intl.NumberFormat("en-US", xqqCodeOptions);
+
+assertParts(xqqMoneyCode, 25,
+            [Currency("XQQ"), Literal("\xA0"), Integer("25")]);
+
+// Test currencyDisplay: "name".
+var usdNameOptions =
+  {
+    style: "currency",
+    currency: "USD",
+    currencyDisplay: "name",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var usDollarsName = new Intl.NumberFormat("en-US", usdNameOptions);
+
+assertParts(usDollarsName, 25,
+            [Integer("25"), Literal(" "), Currency("US dollars")]);
+
+var usdNameGroupingOptions =
+  {
+    style: "currency",
+    currency: "USD",
+    currencyDisplay: "name",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var usDollarsNameGrouping =
+  new Intl.NumberFormat("en-US", usdNameGroupingOptions);
+
+assertParts(usDollarsNameGrouping, 12345678,
+            [Integer("12"),
+             Group(","),
+             Integer("345"),
+             Group(","),
+             Integer("678"),
+             Literal(" "),
+             Currency("US dollars")]);
+
+// But if the implementation doesn't recognize the currency, the provided code
+// is used in place of a proper name, unmolested.
+var xqqNameOptions =
+  {
+    style: "currency",
+    currency: "XQQ",
+    currencyDisplay: "name",
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+var xqqMoneyName = new Intl.NumberFormat("en-US", xqqNameOptions);
+
+assertParts(xqqMoneyName, 25,
+            [Integer("25"), Literal(" "), Currency("XQQ")]);
+
+// Test some currencies with fractional components.
+
+var usdNameFractionOptions =
+  {
+    style: "currency",
+    currency: "USD",
+    currencyDisplay: "name",
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+  };
+var usdNameFractionFormatter =
+  new Intl.NumberFormat("en-US", usdNameFractionOptions);
+
+// The US national surplus (i.e. debt) as of October 18, 2016.  (Replicating
+// data from a comment in builtin/Intl/NumberFormat.cpp.)
+var usNationalSurplus = -19766580028249.41;
+
+assertParts(usdNameFractionFormatter, usNationalSurplus,
+            [MinusSign("-"),
+             Integer("19"),
+             Group(","),
+             Integer("766"),
+             Group(","),
+             Integer("580"),
+             Group(","),
+             Integer("028"),
+             Group(","),
+             Integer("249"),
+             Decimal("."),
+             Fraction("41"),
+             Literal(" "),
+             Currency("US dollars")]);
+
+// Percents in various forms.
+
+var usPercentOptions =
+  {
+    style: "percent",
+    minimumFractionDigits: 1,
+    maximumFractionDigits: 1,
+  };
+var usPercentFormatter =
+  new Intl.NumberFormat("en-US", usPercentOptions);
+
+assertParts(usPercentFormatter, 0.375,
+            [Integer("37"), Decimal("."), Fraction("5"), PercentSign("%")]);
+
+assertParts(usPercentFormatter, -1284.375,
+            [MinusSign("-"),
+             Integer("128"),
+             Group(","),
+             Integer("437"),
+             Decimal("."),
+             Fraction("5"),
+             PercentSign("%")]);
+
+assertParts(usPercentFormatter, NaN,
+            [Nan("NaN"), PercentSign("%")]);
+
+assertParts(usPercentFormatter, Infinity,
+            [Inf("∞"), PercentSign("%")]);
+
+assertParts(usPercentFormatter, -Infinity,
+            [MinusSign("-"), Inf("∞"), PercentSign("%")]);
+
+var dePercentOptions =
+  {
+    style: "percent",
+    minimumFractionDigits: 1,
+    maximumFractionDigits: 1,
+  };
+var dePercentFormatter =
+  new Intl.NumberFormat("de", dePercentOptions);
+
+assertParts(dePercentFormatter, 0.375,
+            [Integer("37"), Decimal(","), Fraction("5"), Literal("\xA0"), PercentSign("%")]);
+
+assertParts(dePercentFormatter, -1284.375,
+            [MinusSign("-"),
+             Integer("128"),
+             Group("."),
+             Integer("437"),
+             Decimal(","),
+             Fraction("5"),
+             Literal("\xA0"),
+             PercentSign("%")]);
+
+assertParts(dePercentFormatter, NaN,
+            [Nan("NaN"), Literal("\xA0"), PercentSign("%")]);
+
+assertParts(dePercentFormatter, Infinity,
+            [Inf("∞"), Literal("\xA0"), PercentSign("%")]);
+
+assertParts(dePercentFormatter, -Infinity,
+            [MinusSign("-"), Inf("∞"), Literal("\xA0"), PercentSign("%")]);
+
+var arPercentOptions =
+  {
+    style: "percent",
+    minimumFractionDigits: 2,
+  };
+var arPercentFormatter =
+  new Intl.NumberFormat("ar-IQ", arPercentOptions);
+
+assertParts(arPercentFormatter, -135.32,
+            [Literal("\u{061C}"),
+             MinusSign("-"),
+             Integer("١٣"),
+             Group("٬"),
+             Integer("٥٣٢"),
+             Decimal("٫"),
+             Fraction("٠٠"),
+             PercentSign("٪"),
+             Literal("\u{061C}")]);
+
+// Decimals.
+
+var usDecimalOptions =
+  {
+    style: "decimal",
+    maximumFractionDigits: 7 // minimum defaults to 0
+  };
+var usDecimalFormatter =
+  new Intl.NumberFormat("en-US", usDecimalOptions);
+
+assertParts(usDecimalFormatter, 42,
+            [Integer("42")]);
+
+assertParts(usDecimalFormatter, 1337,
+            [Integer("1"), Group(","), Integer("337")]);
+
+assertParts(usDecimalFormatter, -6.25,
+            [MinusSign("-"), Integer("6"), Decimal("."), Fraction("25")]);
+
+assertParts(usDecimalFormatter, -1376.25,
+            [MinusSign("-"),
+             Integer("1"),
+             Group(","),
+             Integer("376"),
+             Decimal("."),
+             Fraction("25")]);
+
+assertParts(usDecimalFormatter, 124816.8359375,
+            [Integer("124"),
+             Group(","),
+             Integer("816"),
+             Decimal("."),
+             Fraction("8359375")]);
+
+var usNoGroupingDecimalOptions =
+  {
+    style: "decimal",
+    useGrouping: false,
+    maximumFractionDigits: 7 // minimum defaults to 0
+  };
+var usNoGroupingDecimalFormatter =
+  new Intl.NumberFormat("en-US", usNoGroupingDecimalOptions);
+
+assertParts(usNoGroupingDecimalFormatter, 1337,
+            [Integer("1337")]);
+
+assertParts(usNoGroupingDecimalFormatter, -6.25,
+            [MinusSign("-"), Integer("6"), Decimal("."), Fraction("25")]);
+
+assertParts(usNoGroupingDecimalFormatter, -1376.25,
+            [MinusSign("-"),
+             Integer("1376"),
+             Decimal("."),
+             Fraction("25")]);
+
+assertParts(usNoGroupingDecimalFormatter, 124816.8359375,
+            [Integer("124816"),
+             Decimal("."),
+             Fraction("8359375")]);
+
+var deDecimalOptions =
+  {
+    style: "decimal",
+    maximumFractionDigits: 7 // minimum defaults to 0
+  };
+var deDecimalFormatter =
+  new Intl.NumberFormat("de-DE", deDecimalOptions);
+
+assertParts(deDecimalFormatter, 42,
+            [Integer("42")]);
+
+assertParts(deDecimalFormatter, 1337,
+            [Integer("1"), Group("."), Integer("337")]);
+
+assertParts(deDecimalFormatter, -6.25,
+            [MinusSign("-"), Integer("6"), Decimal(","), Fraction("25")]);
+
+assertParts(deDecimalFormatter, -1376.25,
+            [MinusSign("-"),
+             Integer("1"),
+             Group("."),
+             Integer("376"),
+             Decimal(","),
+             Fraction("25")]);
+
+assertParts(deDecimalFormatter, 124816.8359375,
+            [Integer("124"),
+             Group("."),
+             Integer("816"),
+             Decimal(","),
+             Fraction("8359375")]);
+
+var deNoGroupingDecimalOptions =
+  {
+    style: "decimal",
+    useGrouping: false,
+    maximumFractionDigits: 7 // minimum defaults to 0
+  };
+var deNoGroupingDecimalFormatter =
+  new Intl.NumberFormat("de-DE", deNoGroupingDecimalOptions);
+
+assertParts(deNoGroupingDecimalFormatter, 1337,
+            [Integer("1337")]);
+
+assertParts(deNoGroupingDecimalFormatter, -6.25,
+            [MinusSign("-"), Integer("6"), Decimal(","), Fraction("25")]);
+
+assertParts(deNoGroupingDecimalFormatter, -1376.25,
+            [MinusSign("-"),
+             Integer("1376"),
+             Decimal(","),
+             Fraction("25")]);
+
+assertParts(deNoGroupingDecimalFormatter, 124816.8359375,
+            [Integer("124816"),
+             Decimal(","),
+             Fraction("8359375")]);
+
+//-----------------------------------------------------------------------------
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0, 'ok');
+
+print("Tests complete");
diff --git a/js/src/tests/non262/Intl/NumberFormat/formatting-NaN.js b/js/src/tests/non262/Intl/NumberFormat/formatting-NaN.js
new file mode 100644
index 0000000000..430d74222e
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/formatting-NaN.js
@@ -0,0 +1,35 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/licenses/publicdomain/
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 1484943;
+var summary = "Don't crash doing format/formatToParts on -NaN";
+
+print(BUGNUMBER + ": " + summary);
+
+//-----------------------------------------------------------------------------
+
+assertEq("formatToParts" in Intl.NumberFormat(), true);
+
+var nf = new Intl.NumberFormat("en-US");
+var parts;
+
+var values = [NaN, -NaN];
+
+for (var v of values)
+{
+  assertEq(nf.format(v), "NaN");
+
+  parts = nf.formatToParts(v);
+  assertEq(parts.length, 1);
+  assertEq(parts[0].type, "nan");
+  assertEq(parts[0].value, "NaN");
+}
+
+//-----------------------------------------------------------------------------
+
+if (typeof reportCompare === "function")
+  reportCompare(0, 0, 'ok');
+
+print("Tests complete");
diff --git a/js/src/tests/non262/Intl/NumberFormat/negativeZeroFractionDigits.js b/js/src/tests/non262/Intl/NumberFormat/negativeZeroFractionDigits.js
new file mode 100644
index 0000000000..0db461f50e
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/negativeZeroFractionDigits.js
@@ -0,0 +1,21 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const optionsList = [
+    {minimumFractionDigits: -0, maximumFractionDigits: -0},
+    {minimumFractionDigits: -0, maximumFractionDigits: +0},
+    {minimumFractionDigits: +0, maximumFractionDigits: -0},
+    {minimumFractionDigits: +0, maximumFractionDigits: +0},
+];
+
+for (let options of optionsList) {
+    let numberFormat = new Intl.NumberFormat("en-US", options);
+
+    let {minimumFractionDigits, maximumFractionDigits} = numberFormat.resolvedOptions();
+    assertEq(minimumFractionDigits, +0);
+    assertEq(maximumFractionDigits, +0);
+
+    assertEq(numberFormat.format(123), "123");
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/notation-compact-long.js b/js/src/tests/non262/Intl/NumberFormat/notation-compact-long.js
new file mode 100644
index 0000000000..80c3416afb
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/notation-compact-long.js
@@ -0,0 +1,139 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Decimal, Fraction, Group, Literal,
+    Compact,
+} = NumberFormatParts;
+
+const testcases = [
+    {
+        locale: "en",
+        options: {
+            notation: "compact",
+            compactDisplay: "long",
+        },
+        values: [
+            {value: +0, string: "0", parts: [Integer("0")]},
+            {value: -0, string: "-0", parts: [MinusSign("-"), Integer("0")]},
+            {value: 0n, string: "0", parts: [Integer("0")]},
+
+            {value: 1, string: "1", parts: [Integer("1")]},
+            {value: 10, string: "10", parts: [Integer("10")]},
+            {value: 100, string: "100", parts: [Integer("100")]},
+            {value: 1000, string: "1 thousand", parts: [Integer("1"), Literal(" "), Compact("thousand")]},
+            {value: 10000, string: "10 thousand", parts: [Integer("10"), Literal(" "), Compact("thousand")]},
+            {value: 100000, string: "100 thousand", parts: [Integer("100"), Literal(" "), Compact("thousand")]},
+            {value: 1000000, string: "1 million", parts: [Integer("1"), Literal(" "), Compact("million")]},
+            {value: 10000000, string: "10 million", parts: [Integer("10"), Literal(" "), Compact("million")]},
+            {value: 100000000, string: "100 million", parts: [Integer("100"), Literal(" "), Compact("million")]},
+            {value: 1000000000, string: "1 billion", parts: [Integer("1"), Literal(" "), Compact("billion")]},
+            {value: 10000000000, string: "10 billion", parts: [Integer("10"), Literal(" "), Compact("billion")]},
+            {value: 100000000000, string: "100 billion", parts: [Integer("100"), Literal(" "), Compact("billion")]},
+            {value: 1000000000000, string: "1 trillion", parts: [Integer("1"), Literal(" "), Compact("trillion")]},
+            {value: 10000000000000, string: "10 trillion", parts: [Integer("10"), Literal(" "), Compact("trillion")]},
+            {value: 100000000000000, string: "100 trillion", parts: [Integer("100"), Literal(" "), Compact("trillion")]},
+            {value: 1000000000000000, string: "1000 trillion", parts: [Integer("1000"), Literal(" "), Compact("trillion")]},
+            {value: 10000000000000000, string: "10,000 trillion", parts: [Integer("10"), Group(","), Integer("000"), Literal(" "), Compact("trillion")]},
+            {value: 100000000000000000, string: "100,000 trillion", parts: [Integer("100"), Group(","), Integer("000"), Literal(" "), Compact("trillion")]},
+
+            {value: 1n, string: "1", parts: [Integer("1")]},
+            {value: 10n, string: "10", parts: [Integer("10")]},
+            {value: 100n, string: "100", parts: [Integer("100")]},
+            {value: 1000n, string: "1 thousand", parts: [Integer("1"), Literal(" "), Compact("thousand")]},
+            {value: 10000n, string: "10 thousand", parts: [Integer("10"), Literal(" "), Compact("thousand")]},
+            {value: 100000n, string: "100 thousand", parts: [Integer("100"), Literal(" "), Compact("thousand")]},
+            {value: 1000000n, string: "1 million", parts: [Integer("1"), Literal(" "), Compact("million")]},
+            {value: 10000000n, string: "10 million", parts: [Integer("10"), Literal(" "), Compact("million")]},
+            {value: 100000000n, string: "100 million", parts: [Integer("100"), Literal(" "), Compact("million")]},
+            {value: 1000000000n, string: "1 billion", parts: [Integer("1"), Literal(" "), Compact("billion")]},
+            {value: 10000000000n, string: "10 billion", parts: [Integer("10"), Literal(" "), Compact("billion")]},
+            {value: 100000000000n, string: "100 billion", parts: [Integer("100"), Literal(" "), Compact("billion")]},
+            {value: 1000000000000n, string: "1 trillion", parts: [Integer("1"), Literal(" "), Compact("trillion")]},
+            {value: 10000000000000n, string: "10 trillion", parts: [Integer("10"), Literal(" "), Compact("trillion")]},
+            {value: 100000000000000n, string: "100 trillion", parts: [Integer("100"), Literal(" "), Compact("trillion")]},
+            {value: 1000000000000000n, string: "1000 trillion", parts: [Integer("1000"), Literal(" "), Compact("trillion")]},
+            {value: 10000000000000000n, string: "10,000 trillion", parts: [Integer("10"), Group(","), Integer("000"), Literal(" "), Compact("trillion")]},
+            {value: 100000000000000000n, string: "100,000 trillion", parts: [Integer("100"), Group(","), Integer("000"), Literal(" "), Compact("trillion")]},
+
+            {value: 0.1, string: "0.1", parts: [Integer("0"), Decimal("."), Fraction("1")]},
+            {value: 0.01, string: "0.01", parts: [Integer("0"), Decimal("."), Fraction("01")]},
+            {value: 0.001, string: "0.001", parts: [Integer("0"), Decimal("."), Fraction("001")]},
+            {value: 0.0001, string: "0.0001", parts: [Integer("0"), Decimal("."), Fraction("0001")]},
+            {value: 0.00001, string: "0.00001", parts: [Integer("0"), Decimal("."), Fraction("00001")]},
+            {value: 0.000001, string: "0.000001", parts: [Integer("0"), Decimal("."), Fraction("000001")]},
+            {value: 0.0000001, string: "0.0000001", parts: [Integer("0"), Decimal("."), Fraction("0000001")]},
+
+            {value: 12, string: "12", parts: [Integer("12")]},
+            {value: 123, string: "123", parts: [Integer("123")]},
+            {value: 1234, string: "1.2 thousand", parts: [Integer("1"), Decimal("."), Fraction("2"), Literal(" "), Compact("thousand")]},
+            {value: 12345, string: "12 thousand", parts: [Integer("12"), Literal(" "), Compact("thousand")]},
+            {value: 123456, string: "123 thousand", parts: [Integer("123"), Literal(" "), Compact("thousand")]},
+            {value: 1234567, string: "1.2 million", parts: [Integer("1"), Decimal("."), Fraction("2"), Literal(" "), Compact("million")]},
+            {value: 12345678, string: "12 million", parts: [Integer("12"), Literal(" "), Compact("million")]},
+            {value: 123456789, string: "123 million", parts: [Integer("123"), Literal(" "), Compact("million")]},
+
+            {value:  Infinity, string: "∞", parts: [Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // The "{compactName}" placeholder may have different plural forms.
+    {
+        locale: "de",
+        options: {
+            notation: "compact",
+            compactDisplay: "long",
+        },
+        values: [
+            {value: 1e6, string: "1 Million", parts: [Integer("1"), Literal(" "), Compact("Million")]},
+            {value: 2e6, string: "2 Millionen", parts: [Integer("2"), Literal(" "), Compact("Millionen")]},
+            {value: 1e9, string: "1 Milliarde", parts: [Integer("1"), Literal(" "), Compact("Milliarde")]},
+            {value: 2e9, string: "2 Milliarden", parts: [Integer("2"), Literal(" "), Compact("Milliarden")]},
+        ],
+    },
+
+    // Digits are grouped in myriads (every 10,000) in Japanese.
+    {
+        locale: "ja",
+        options: {
+            notation: "compact",
+            compactDisplay: "long",
+        },
+        values: [
+            {value: 1, string: "1", parts: [Integer("1")]},
+            {value: 10, string: "10", parts: [Integer("10")]},
+            {value: 100, string: "100", parts: [Integer("100")]},
+            {value: 1000, string: "1000", parts: [Integer("1000")]},
+
+            {value: 10e3, string: "1\u4E07", parts: [Integer("1"), Compact("\u4E07")]},
+            {value: 100e3, string: "10\u4E07", parts: [Integer("10"), Compact("\u4E07")]},
+            {value: 1000e3, string: "100\u4E07", parts: [Integer("100"), Compact("\u4E07")]},
+            {value: 10000e3, string: "1000\u4E07", parts: [Integer("1000"), Compact("\u4E07")]},
+
+            {value: 10e7, string: "1\u5104", parts: [Integer("1"), Compact("\u5104")]},
+            {value: 100e7, string: "10\u5104", parts: [Integer("10"), Compact("\u5104")]},
+            {value: 1000e7, string: "100\u5104", parts: [Integer("100"), Compact("\u5104")]},
+            {value: 10000e7, string: "1000\u5104", parts: [Integer("1000"), Compact("\u5104")]},
+
+            {value: 10e11, string: "1\u5146", parts: [Integer("1"), Compact("\u5146")]},
+            {value: 100e11, string: "10\u5146", parts: [Integer("10"), Compact("\u5146")]},
+            {value: 1000e11, string: "100\u5146", parts: [Integer("100"), Compact("\u5146")]},
+            {value: 10000e11, string: "1000\u5146", parts: [Integer("1000"), Compact("\u5146")]},
+
+            {value: 10e15, string: "1\u4EAC", parts: [Integer("1"), Compact("\u4EAC")]},
+            {value: 100e15, string: "10\u4EAC", parts: [Integer("10"), Compact("\u4EAC")]},
+            {value: 1000e15, string: "100\u4EAC", parts: [Integer("100"), Compact("\u4EAC")]},
+            {value: 10000e15, string: "1000\u4EAC", parts: [Integer("1000"), Compact("\u4EAC")]},
+
+            {value: 100000e15, string: "10,000\u4EAC", parts: [Integer("10"), Group(","), Integer("000"), Compact("\u4EAC")]},
+        ],
+    },
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/notation-compact-short.js b/js/src/tests/non262/Intl/NumberFormat/notation-compact-short.js
new file mode 100644
index 0000000000..f3a546294d
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/notation-compact-short.js
@@ -0,0 +1,136 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Decimal, Fraction, Group, Literal,
+    Compact,
+} = NumberFormatParts;
+
+const testcases = [
+    {
+        locale: "en",
+        options: {
+            notation: "compact",
+            compactDisplay: "short",
+        },
+        values: [
+            {value: +0, string: "0", parts: [Integer("0")]},
+            {value: -0, string: "-0", parts: [MinusSign("-"), Integer("0")]},
+            {value: 0n, string: "0", parts: [Integer("0")]},
+
+            {value: 1, string: "1", parts: [Integer("1")]},
+            {value: 10, string: "10", parts: [Integer("10")]},
+            {value: 100, string: "100", parts: [Integer("100")]},
+            {value: 1000, string: "1K", parts: [Integer("1"), Compact("K")]},
+            {value: 10000, string: "10K", parts: [Integer("10"), Compact("K")]},
+            {value: 100000, string: "100K", parts: [Integer("100"), Compact("K")]},
+            {value: 1000000, string: "1M", parts: [Integer("1"), Compact("M")]},
+            {value: 10000000, string: "10M", parts: [Integer("10"), Compact("M")]},
+            {value: 100000000, string: "100M", parts: [Integer("100"), Compact("M")]},
+            {value: 1000000000, string: "1B", parts: [Integer("1"), Compact("B")]},
+            {value: 10000000000, string: "10B", parts: [Integer("10"), Compact("B")]},
+            {value: 100000000000, string: "100B", parts: [Integer("100"), Compact("B")]},
+            {value: 1000000000000, string: "1T", parts: [Integer("1"), Compact("T")]},
+            {value: 10000000000000, string: "10T", parts: [Integer("10"), Compact("T")]},
+            {value: 100000000000000, string: "100T", parts: [Integer("100"), Compact("T")]},
+            {value: 1000000000000000, string: "1000T", parts: [Integer("1000"), Compact("T")]},
+            {value: 10000000000000000, string: "10,000T", parts: [Integer("10"), Group(","), Integer("000"), Compact("T")]},
+            {value: 100000000000000000, string: "100,000T", parts: [Integer("100"), Group(","), Integer("000"), Compact("T")]},
+
+            {value: 1n, string: "1", parts: [Integer("1")]},
+            {value: 10n, string: "10", parts: [Integer("10")]},
+            {value: 100n, string: "100", parts: [Integer("100")]},
+            {value: 1000n, string: "1K", parts: [Integer("1"), Compact("K")]},
+            {value: 10000n, string: "10K", parts: [Integer("10"), Compact("K")]},
+            {value: 100000n, string: "100K", parts: [Integer("100"), Compact("K")]},
+            {value: 1000000n, string: "1M", parts: [Integer("1"), Compact("M")]},
+            {value: 10000000n, string: "10M", parts: [Integer("10"), Compact("M")]},
+            {value: 100000000n, string: "100M", parts: [Integer("100"), Compact("M")]},
+            {value: 1000000000n, string: "1B", parts: [Integer("1"), Compact("B")]},
+            {value: 10000000000n, string: "10B", parts: [Integer("10"), Compact("B")]},
+            {value: 100000000000n, string: "100B", parts: [Integer("100"), Compact("B")]},
+            {value: 1000000000000n, string: "1T", parts: [Integer("1"), Compact("T")]},
+            {value: 10000000000000n, string: "10T", parts: [Integer("10"), Compact("T")]},
+            {value: 100000000000000n, string: "100T", parts: [Integer("100"), Compact("T")]},
+            {value: 1000000000000000n, string: "1000T", parts: [Integer("1000"), Compact("T")]},
+            {value: 10000000000000000n, string: "10,000T", parts: [Integer("10"), Group(","), Integer("000"), Compact("T")]},
+            {value: 100000000000000000n, string: "100,000T", parts: [Integer("100"), Group(","), Integer("000"), Compact("T")]},
+
+            {value: 0.1, string: "0.1", parts: [Integer("0"), Decimal("."), Fraction("1")]},
+            {value: 0.01, string: "0.01", parts: [Integer("0"), Decimal("."), Fraction("01")]},
+            {value: 0.001, string: "0.001", parts: [Integer("0"), Decimal("."), Fraction("001")]},
+            {value: 0.0001, string: "0.0001", parts: [Integer("0"), Decimal("."), Fraction("0001")]},
+            {value: 0.00001, string: "0.00001", parts: [Integer("0"), Decimal("."), Fraction("00001")]},
+            {value: 0.000001, string: "0.000001", parts: [Integer("0"), Decimal("."), Fraction("000001")]},
+            {value: 0.0000001, string: "0.0000001", parts: [Integer("0"), Decimal("."), Fraction("0000001")]},
+
+            {value: 12, string: "12", parts: [Integer("12")]},
+            {value: 123, string: "123", parts: [Integer("123")]},
+            {value: 1234, string: "1.2K", parts: [Integer("1"), Decimal("."), Fraction("2"), Compact("K")]},
+            {value: 12345, string: "12K", parts: [Integer("12"), Compact("K")]},
+            {value: 123456, string: "123K", parts: [Integer("123"), Compact("K")]},
+            {value: 1234567, string: "1.2M", parts: [Integer("1"), Decimal("."), Fraction("2"), Compact("M")]},
+            {value: 12345678, string: "12M", parts: [Integer("12"), Compact("M")]},
+            {value: 123456789, string: "123M", parts: [Integer("123"), Compact("M")]},
+
+            {value:  Infinity, string: "∞", parts: [Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // Compact symbol can consist of multiple characters, e.g. when it's an abbreviation.
+    {
+        locale: "de",
+        options: {
+            notation: "compact",
+            compactDisplay: "short",
+        },
+        values: [
+            {value: 1e6, string: "1\u00A0Mio.", parts: [Integer("1"), Literal("\u00A0"), Compact("Mio.")]},
+            {value: 1e9, string: "1\u00A0Mrd.", parts: [Integer("1"), Literal("\u00A0"), Compact("Mrd.")]},
+            {value: 1e12, string: "1\u00A0Bio.", parts: [Integer("1"), Literal("\u00A0"), Compact("Bio.")]},
+
+            // CLDR doesn't support "Billiarde" (Brd.), Trillion (Trill.), etc.
+            {value: 1e15, string: "1000\u00A0Bio.", parts: [Integer("1000"), Literal("\u00A0"), Compact("Bio.")]},
+        ],
+    },
+
+    // Digits are grouped in myriads (every 10,000) in Chinese.
+    {
+        locale: "zh",
+        options: {
+            notation: "compact",
+            compactDisplay: "short",
+        },
+        values: [
+            {value: 1, string: "1", parts: [Integer("1")]},
+            {value: 10, string: "10", parts: [Integer("10")]},
+            {value: 100, string: "100", parts: [Integer("100")]},
+            {value: 1000, string: "1000", parts: [Integer("1000")]},
+
+            {value: 10e3, string: "1\u4E07", parts: [Integer("1"), Compact("\u4E07")]},
+            {value: 100e3, string: "10\u4E07", parts: [Integer("10"), Compact("\u4E07")]},
+            {value: 1000e3, string: "100\u4E07", parts: [Integer("100"), Compact("\u4E07")]},
+            {value: 10000e3, string: "1000\u4E07", parts: [Integer("1000"), Compact("\u4E07")]},
+
+            {value: 10e7, string: "1\u4EBF", parts: [Integer("1"), Compact("\u4EBF")]},
+            {value: 100e7, string: "10\u4EBF", parts: [Integer("10"), Compact("\u4EBF")]},
+            {value: 1000e7, string: "100\u4EBF", parts: [Integer("100"), Compact("\u4EBF")]},
+            {value: 10000e7, string: "1000\u4EBF", parts: [Integer("1000"), Compact("\u4EBF")]},
+
+            {value: 10e11, string: "1\u4E07\u4EBF", parts: [Integer("1"), Compact("\u4E07\u4EBF")]},
+            {value: 100e11, string: "10\u4E07\u4EBF", parts: [Integer("10"), Compact("\u4E07\u4EBF")]},
+            {value: 1000e11, string: "100\u4E07\u4EBF", parts: [Integer("100"), Compact("\u4E07\u4EBF")]},
+            {value: 10000e11, string: "1000\u4E07\u4EBF", parts: [Integer("1000"), Compact("\u4E07\u4EBF")]},
+
+            {value: 100000e11, string: "10,000\u4E07\u4EBF", parts: [Integer("10"), Group(","), Integer("000"), Compact("\u4E07\u4EBF")]},
+        ],
+    },
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/notation-compact-with-fraction-digits.js b/js/src/tests/non262/Intl/NumberFormat/notation-compact-with-fraction-digits.js
new file mode 100644
index 0000000000..4bdf26b9ad
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/notation-compact-with-fraction-digits.js
@@ -0,0 +1,17 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+let nf = new Intl.NumberFormat("en", {
+  minimumFractionDigits: 0,
+  maximumFractionDigits: 2,
+  notation: "compact",
+});
+
+assertEq(nf.format(1500), "1.5K");
+assertEq(nf.format(1520), "1.52K");
+assertEq(nf.format(1540), "1.54K");
+assertEq(nf.format(1550), "1.55K");
+assertEq(nf.format(1560), "1.56K");
+assertEq(nf.format(1580), "1.58K");
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/notation-engineering.js b/js/src/tests/non262/Intl/NumberFormat/notation-engineering.js
new file mode 100644
index 0000000000..b4c0e19e53
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/notation-engineering.js
@@ -0,0 +1,136 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Decimal, Fraction, Group,
+    ExponentSeparator, ExponentInteger, ExponentMinusSign,
+} = NumberFormatParts;
+
+const testcases = [
+    {
+        locale: "en",
+        options: {
+            notation: "engineering",
+        },
+        values: [
+            {value: +0, string: "0E0", parts: [Integer("0"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: -0, string: "-0E0", parts: [MinusSign("-"), Integer("0"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 0n, string: "0E0", parts: [Integer("0"), ExponentSeparator("E"), ExponentInteger("0")]},
+
+            {value: 1, string: "1E0", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 10, string: "10E0", parts: [Integer("10"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 100, string: "100E0", parts: [Integer("100"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 1000, string: "1E3", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 10000, string: "10E3", parts: [Integer("10"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 100000, string: "100E3", parts: [Integer("100"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 1000000, string: "1E6", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("6")]},
+
+            {value: 1n, string: "1E0", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 10n, string: "10E0", parts: [Integer("10"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 100n, string: "100E0", parts: [Integer("100"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 1000n, string: "1E3", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 10000n, string: "10E3", parts: [Integer("10"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 100000n, string: "100E3", parts: [Integer("100"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 1000000n, string: "1E6", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("6")]},
+
+            {value: 0.1, string: "100E-3", parts: [Integer("100"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")]},
+            {value: 0.01, string: "10E-3", parts: [Integer("10"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")]},
+            {value: 0.001, string: "1E-3", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")]},
+            {value: 0.0001, string: "100E-6", parts: [Integer("100"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("6")]},
+            {value: 0.00001, string: "10E-6", parts: [Integer("10"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("6")]},
+            {value: 0.000001, string: "1E-6", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("6")]},
+            {value: 0.0000001, string: "100E-9", parts: [Integer("100"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("9")]},
+
+            {value:  Infinity, string: "∞", parts: [Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // Exponent modifications take place early, so while in the "standard" notation
+    // `Intl.NumberFormat("en", {maximumFractionDigits: 0}).format(0.1)` returns "0", for
+    // "engineering" notation the result string is not "0", but instead "100E-3".
+
+    {
+        locale: "en",
+        options: {
+            notation: "engineering",
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: 0.1, string: "100E-3", parts: [
+                Integer("100"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "engineering",
+            minimumFractionDigits: 4,
+        },
+        values: [
+            {value: 10, string: "10.0000E0", parts: [
+                Integer("10"), Decimal("."), Fraction("0000"), ExponentSeparator("E"), ExponentInteger("0")
+            ]},
+            {value: 0.1, string: "100.0000E-3", parts: [
+                Integer("100"), Decimal("."), Fraction("0000"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "engineering",
+            minimumIntegerDigits: 4,
+        },
+        values: [
+            {value: 10, string: "0,010E0", parts: [
+                Integer("0"), Group(","), Integer("010"), ExponentSeparator("E"), ExponentInteger("0")
+            ]},
+            {value: 0.1, string: "0,100E-3", parts: [
+                Integer("0"), Group(","), Integer("100"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "engineering",
+            minimumSignificantDigits: 4,
+        },
+        values: [
+            {value: 10, string: "10.00E0", parts: [
+                Integer("10"), Decimal("."), Fraction("00"), ExponentSeparator("E"), ExponentInteger("0")
+            ]},
+            {value: 0.1, string: "100.0E-3", parts: [
+                Integer("100"), Decimal("."), Fraction("0"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "engineering",
+            maximumSignificantDigits: 1,
+        },
+        values: [
+            {value: 12, string: "10E0", parts: [
+                Integer("10"), ExponentSeparator("E"), ExponentInteger("0")
+            ]},
+            {value: 0.12, string: "100E-3", parts: [
+                Integer("100"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")
+            ]},
+        ],
+    },
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/notation-scientific.js b/js/src/tests/non262/Intl/NumberFormat/notation-scientific.js
new file mode 100644
index 0000000000..f14a660129
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/notation-scientific.js
@@ -0,0 +1,136 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Decimal, Fraction, Group,
+    ExponentSeparator, ExponentInteger, ExponentMinusSign,
+} = NumberFormatParts;
+
+const testcases = [
+    {
+        locale: "en",
+        options: {
+            notation: "scientific",
+        },
+        values: [
+            {value: +0, string: "0E0", parts: [Integer("0"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: -0, string: "-0E0", parts: [MinusSign("-"), Integer("0"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 0n, string: "0E0", parts: [Integer("0"), ExponentSeparator("E"), ExponentInteger("0")]},
+
+            {value: 1, string: "1E0", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 10, string: "1E1", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("1")]},
+            {value: 100, string: "1E2", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("2")]},
+            {value: 1000, string: "1E3", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 10000, string: "1E4", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("4")]},
+            {value: 100000, string: "1E5", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("5")]},
+            {value: 1000000, string: "1E6", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("6")]},
+
+            {value: 1n, string: "1E0", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("0")]},
+            {value: 10n, string: "1E1", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("1")]},
+            {value: 100n, string: "1E2", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("2")]},
+            {value: 1000n, string: "1E3", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("3")]},
+            {value: 10000n, string: "1E4", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("4")]},
+            {value: 100000n, string: "1E5", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("5")]},
+            {value: 1000000n, string: "1E6", parts: [Integer("1"), ExponentSeparator("E"), ExponentInteger("6")]},
+
+            {value: 0.1, string: "1E-1", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("1")]},
+            {value: 0.01, string: "1E-2", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("2")]},
+            {value: 0.001, string: "1E-3", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("3")]},
+            {value: 0.0001, string: "1E-4", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("4")]},
+            {value: 0.00001, string: "1E-5", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("5")]},
+            {value: 0.000001, string: "1E-6", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("6")]},
+            {value: 0.0000001, string: "1E-7", parts: [Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("7")]},
+
+            {value:  Infinity, string: "∞", parts: [Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // Exponent modifications take place early, so while in the "standard" notation
+    // `Intl.NumberFormat("en", {maximumFractionDigits: 0}).format(0.1)` returns "0", for
+    // "scientific" notation the result string is not "0", but instead "1E-1".
+
+    {
+        locale: "en",
+        options: {
+            notation: "scientific",
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: 0.1, string: "1E-1", parts: [
+                Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("1")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "scientific",
+            minimumFractionDigits: 4,
+        },
+        values: [
+            {value: 10, string: "1.0000E1", parts: [
+                Integer("1"), Decimal("."), Fraction("0000"), ExponentSeparator("E"), ExponentInteger("1")
+            ]},
+            {value: 0.1, string: "1.0000E-1", parts: [
+                Integer("1"), Decimal("."), Fraction("0000"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("1")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "scientific",
+            minimumIntegerDigits: 4,
+        },
+        values: [
+            {value: 10, string: "0,001E1", parts: [
+                Integer("0"), Group(","), Integer("001"), ExponentSeparator("E"), ExponentInteger("1")
+            ]},
+            {value: 0.1, string: "0,001E-1", parts: [
+                Integer("0"), Group(","), Integer("001"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("1")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "scientific",
+            minimumSignificantDigits: 4,
+        },
+        values: [
+            {value: 10, string: "1.000E1", parts: [
+                Integer("1"), Decimal("."), Fraction("000"), ExponentSeparator("E"), ExponentInteger("1")
+            ]},
+            {value: 0.1, string: "1.000E-1", parts: [
+                Integer("1"), Decimal("."), Fraction("000"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("1")
+            ]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            notation: "scientific",
+            maximumSignificantDigits: 1,
+        },
+        values: [
+            {value: 12, string: "1E1", parts: [
+                Integer("1"), ExponentSeparator("E"), ExponentInteger("1")
+            ]},
+            {value: 0.12, string: "1E-1", parts: [
+                Integer("1"), ExponentSeparator("E"), ExponentMinusSign("-"), ExponentInteger("1")
+            ]},
+        ],
+    },
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/numberingSystem-format.js b/js/src/tests/non262/Intl/NumberFormat/numberingSystem-format.js
new file mode 100644
index 0000000000..c0b9ba78ed
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/numberingSystem-format.js
@@ -0,0 +1,18 @@
+for (let [numberingSystem, {digits, algorithmic}] of Object.entries(numberingSystems)) {
+  if (algorithmic) {
+    // We don't yet support algorithmic numbering systems.
+    continue;
+  }
+
+  let nf = new Intl.NumberFormat("en", {numberingSystem});
+
+  assertEq([...digits].length, 10, "expect exactly ten digits for each numbering system");
+
+  let i = 0;
+  for (let digit of digits) {
+    assertEq(nf.format(i++), digit);
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/numberingSystem-option.js b/js/src/tests/non262/Intl/NumberFormat/numberingSystem-option.js
new file mode 100644
index 0000000000..4624ee5192
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/numberingSystem-option.js
@@ -0,0 +1,60 @@
+const defaultLocale = "en";
+const defaultNumberingSystem = new Intl.NumberFormat(defaultLocale).resolvedOptions().numberingSystem;
+
+function createWithLocale(locale, numberingSystem) {
+  return new Intl.NumberFormat(locale, {numberingSystem});
+}
+
+function create(numberingSystem) {
+  return createWithLocale(defaultLocale, numberingSystem);
+}
+
+// Empty string should throw.
+assertThrowsInstanceOf(() => create(""), RangeError);
+
+// Trailing \0 should throw.
+assertThrowsInstanceOf(() => create("latn\0"), RangeError);
+
+// Too short or too long strings should throw.
+assertThrowsInstanceOf(() => create("a"), RangeError);
+assertThrowsInstanceOf(() => create("toolongstring"), RangeError);
+
+// Throw even when prefix is valid.
+assertThrowsInstanceOf(() => create("latn-toolongstring"), RangeError);
+
+// |numberingSystem| can be set to |undefined|.
+let nf = create(undefined);
+assertEq(nf.resolvedOptions().numberingSystem, defaultNumberingSystem);
+
+// Unsupported numbering systems are ignored.
+nf = create("xxxxxxxx");
+assertEq(nf.resolvedOptions().numberingSystem, defaultNumberingSystem);
+
+// Numbering system in options overwrite Unicode extension keyword.
+nf = createWithLocale(`${defaultLocale}-u-nu-thai`, "arab");
+assertEq(nf.resolvedOptions().locale, defaultLocale);
+assertEq(nf.resolvedOptions().numberingSystem, "arab");
+
+// |numberingSystem| option ignores case.
+nf = create("ARAB");
+assertEq(nf.resolvedOptions().locale, defaultLocale);
+assertEq(nf.resolvedOptions().numberingSystem, "arab");
+
+for (let [numberingSystem, {algorithmic}] of Object.entries(numberingSystems)) {
+  let nf1 = new Intl.NumberFormat(`${defaultLocale}-u-nu-${numberingSystem}`);
+  let nf2 = new Intl.NumberFormat(defaultLocale, {numberingSystem});
+
+  if (!algorithmic) {
+    assertEq(nf1.resolvedOptions().numberingSystem, numberingSystem);
+    assertEq(nf2.resolvedOptions().numberingSystem, numberingSystem);
+  } else {
+    // We don't yet support algorithmic numbering systems.
+    assertEq(nf1.resolvedOptions().numberingSystem, defaultNumberingSystem);
+    assertEq(nf2.resolvedOptions().numberingSystem, defaultNumberingSystem);
+  }
+
+  assertEq(nf2.format(0), nf1.format(0));
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/options-emulate-undefined.js b/js/src/tests/non262/Intl/NumberFormat/options-emulate-undefined.js
new file mode 100644
index 0000000000..ddb2d61350
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/options-emulate-undefined.js
@@ -0,0 +1,13 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// createIsHTMLDDA is only available when running tests in the shell,
+// not the browser
+if (typeof createIsHTMLDDA === "function") {
+  let nf = new Intl.NumberFormat('en-US', createIsHTMLDDA());
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/remove-unicode-extensions.js b/js/src/tests/non262/Intl/NumberFormat/remove-unicode-extensions.js
new file mode 100644
index 0000000000..87cfc317cb
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/remove-unicode-extensions.js
@@ -0,0 +1,25 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Locale processing is supposed to internally remove any Unicode extension
+// sequences in the locale.  Test that various weird testcases invoking
+// algorithmic edge cases don't assert or throw exceptions.
+
+var weirdCases =
+  [
+   "en-x-u-foo",
+   "en-a-bar-x-u-foo",
+   "en-x-u-foo-a-bar",
+   "en-a-bar-u-baz-x-u-foo",
+  ];
+
+for (var locale of weirdCases)
+  Intl.NumberFormat(locale).format(5);
+
+assertThrowsInstanceOf(() => Intl.NumberFormat("x-u-foo"), RangeError);
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/rounding-increment.js b/js/src/tests/non262/Intl/NumberFormat/rounding-increment.js
new file mode 100644
index 0000000000..84d4480227
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/rounding-increment.js
@@ -0,0 +1,102 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+// Nickel rounding.
+{
+  let nf = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+    roundingIncrement: 5,
+  });
+
+  assertEq(nf.format(1.22), "1.20");
+  assertEq(nf.format(1.224), "1.20");
+  assertEq(nf.format(1.225), "1.25");
+  assertEq(nf.format(1.23), "1.25");
+}
+
+// Dime rounding.
+{
+  let nf = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+    roundingIncrement: 10,
+  });
+
+  assertEq(nf.format(1.24), "1.20");
+  assertEq(nf.format(1.249), "1.20");
+  assertEq(nf.format(1.250), "1.30");
+  assertEq(nf.format(1.25), "1.30");
+}
+
+// Rounding increment option is rounded down.
+{
+  let nf1 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+    roundingIncrement: 10,
+  });
+
+  let nf2 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+    roundingIncrement: 10.1,
+  });
+
+  let nf3 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+    roundingIncrement: 10.9,
+  });
+
+  assertEq(nf1.resolvedOptions().roundingIncrement, 10);
+  assertEq(nf2.resolvedOptions().roundingIncrement, 10);
+  assertEq(nf3.resolvedOptions().roundingIncrement, 10);
+
+  assertEq(nf1.format(123), "120");
+  assertEq(nf2.format(123), "120");
+  assertEq(nf3.format(123), "120");
+}
+
+// |minimumFractionDigits| must be equal to |maximumFractionDigits| when
+// |roundingIncrement| is used.
+//
+// |minimumFractionDigits| defaults to zero.
+{
+  let nf = new Intl.NumberFormat("en", {
+    roundingIncrement: 10,
+    // minimumFractionDigits: 0, (default)
+    maximumFractionDigits: 0,
+  });
+
+  let resolved = nf.resolvedOptions();
+  assertEq(resolved.minimumFractionDigits, 0);
+  assertEq(resolved.maximumFractionDigits, 0);
+  assertEq(resolved.roundingIncrement, 10);
+
+  assertEq(nf.format(123), "120");
+  assertEq(nf.format(123.456), "120");
+}
+
+// |maximumFractionDigits| defaults to three. And because |0 !== 3|, a
+// RangeError is thrown.
+{
+  let options = {
+    roundingIncrement: 10,
+    // minimumFractionDigits: 0, (default)
+    // maximumFractionDigits: 3, (default)
+  };
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("en", options), RangeError);
+}
+
+// Invalid values.
+for (let roundingIncrement of [-1, 0, Infinity, NaN]){
+  let options = {
+    roundingIncrement,
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  };
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("en", options), RangeError);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/rounding-mode.js b/js/src/tests/non262/Intl/NumberFormat/rounding-mode.js
new file mode 100644
index 0000000000..e4b85b0172
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/rounding-mode.js
@@ -0,0 +1,287 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+const tests = [
+  // Special values: Zeros and non-finite values.
+  {
+    value: 0,
+    options: {},
+    roundingModes: {
+      ceil: "0",
+      floor: "0",
+      expand: "0",
+      trunc: "0",
+      halfCeil: "0",
+      halfFloor: "0",
+      halfExpand: "0",
+      halfTrunc: "0",
+      halfEven: "0",
+    },
+  },
+  {
+    value: -0,
+    options: {},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-0",
+      expand: "-0",
+      trunc: "-0",
+      halfCeil: "-0",
+      halfFloor: "-0",
+      halfExpand: "-0",
+      halfTrunc: "-0",
+      halfEven: "-0",
+    },
+  },
+  {
+    value: -Infinity,
+    options: {},
+    roundingModes: {
+      ceil: "-∞",
+      floor: "-∞",
+      expand: "-∞",
+      trunc: "-∞",
+      halfCeil: "-∞",
+      halfFloor: "-∞",
+      halfExpand: "-∞",
+      halfTrunc: "-∞",
+      halfEven: "-∞",
+    },
+  },
+  {
+    value: Infinity,
+    options: {},
+    roundingModes: {
+      ceil: "∞",
+      floor: "∞",
+      expand: "∞",
+      trunc: "∞",
+      halfCeil: "∞",
+      halfFloor: "∞",
+      halfExpand: "∞",
+      halfTrunc: "∞",
+      halfEven: "∞",
+    },
+  },
+  {
+    value: NaN,
+    options: {},
+    roundingModes: {
+      ceil: "NaN",
+      floor: "NaN",
+      expand: "NaN",
+      trunc: "NaN",
+      halfCeil: "NaN",
+      halfFloor: "NaN",
+      halfExpand: "NaN",
+      halfTrunc: "NaN",
+      halfEven: "NaN",
+    },
+  },
+
+  // Integer rounding with positive values.
+  {
+    value: 0.4,
+    options: {maximumFractionDigits: 0},
+    roundingModes: {
+      ceil: "1",
+      floor: "0",
+      expand: "1",
+      trunc: "0",
+      halfCeil: "0",
+      halfFloor: "0",
+      halfExpand: "0",
+      halfTrunc: "0",
+      halfEven: "0",
+    },
+  },
+  {
+    value: 0.5,
+    options: {maximumFractionDigits: 0},
+    roundingModes: {
+      ceil: "1",
+      floor: "0",
+      expand: "1",
+      trunc: "0",
+      halfCeil: "1",
+      halfFloor: "0",
+      halfExpand: "1",
+      halfTrunc: "0",
+      halfEven: "0",
+    },
+  },
+  {
+    value: 0.6,
+    options: {maximumFractionDigits: 0},
+    roundingModes: {
+      ceil: "1",
+      floor: "0",
+      expand: "1",
+      trunc: "0",
+      halfCeil: "1",
+      halfFloor: "1",
+      halfExpand: "1",
+      halfTrunc: "1",
+      halfEven: "1",
+    },
+  },
+
+  // Integer rounding with negative values.
+  {
+    value: -0.4,
+    options: {maximumFractionDigits: 0},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-1",
+      expand: "-1",
+      trunc: "-0",
+      halfCeil: "-0",
+      halfFloor: "-0",
+      halfExpand: "-0",
+      halfTrunc: "-0",
+      halfEven: "-0",
+    },
+  },
+  {
+    value: -0.5,
+    options: {maximumFractionDigits: 0},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-1",
+      expand: "-1",
+      trunc: "-0",
+      halfCeil: "-0",
+      halfFloor: "-1",
+      halfExpand: "-1",
+      halfTrunc: "-0",
+      halfEven: "-0",
+    },
+  },
+  {
+    value: -0.6,
+    options: {maximumFractionDigits: 0},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-1",
+      expand: "-1",
+      trunc: "-0",
+      halfCeil: "-1",
+      halfFloor: "-1",
+      halfExpand: "-1",
+      halfTrunc: "-1",
+      halfEven: "-1",
+    },
+  },
+
+  // Fractional digits rounding with positive values.
+  {
+    value: 0.04,
+    options: {maximumFractionDigits: 1},
+    roundingModes: {
+      ceil: "0.1",
+      floor: "0",
+      expand: "0.1",
+      trunc: "0",
+      halfCeil: "0",
+      halfFloor: "0",
+      halfExpand: "0",
+      halfTrunc: "0",
+      halfEven: "0",
+    },
+  },
+  {
+    value: 0.05,
+    options: {maximumFractionDigits: 1},
+    roundingModes: {
+      ceil: "0.1",
+      floor: "0",
+      expand: "0.1",
+      trunc: "0",
+      halfCeil: "0.1",
+      halfFloor: "0",
+      halfExpand: "0.1",
+      halfTrunc: "0",
+      halfEven: "0",
+    },
+  },
+  {
+    value: 0.06,
+    options: {maximumFractionDigits: 1},
+    roundingModes: {
+      ceil: "0.1",
+      floor: "0",
+      expand: "0.1",
+      trunc: "0",
+      halfCeil: "0.1",
+      halfFloor: "0.1",
+      halfExpand: "0.1",
+      halfTrunc: "0.1",
+      halfEven: "0.1",
+    },
+  },
+
+  // Fractional digits rounding with negative values.
+  {
+    value: -0.04,
+    options: {maximumFractionDigits: 1},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-0.1",
+      expand: "-0.1",
+      trunc: "-0",
+      halfCeil: "-0",
+      halfFloor: "-0",
+      halfExpand: "-0",
+      halfTrunc: "-0",
+      halfEven: "-0",
+    },
+  },
+  {
+    value: -0.05,
+    options: {maximumFractionDigits: 1},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-0.1",
+      expand: "-0.1",
+      trunc: "-0",
+      halfCeil: "-0",
+      halfFloor: "-0.1",
+      halfExpand: "-0.1",
+      halfTrunc: "-0",
+      halfEven: "-0",
+    },
+  },
+  {
+    value: -0.06,
+    options: {maximumFractionDigits: 1},
+    roundingModes: {
+      ceil: "-0",
+      floor: "-0.1",
+      expand: "-0.1",
+      trunc: "-0",
+      halfCeil: "-0.1",
+      halfFloor: "-0.1",
+      halfExpand: "-0.1",
+      halfTrunc: "-0.1",
+      halfEven: "-0.1",
+    },
+  },
+];
+
+for (let {value, options, roundingModes} of tests) {
+  for (let [roundingMode, expected] of Object.entries(roundingModes)) {
+    let nf = new Intl.NumberFormat("en", {...options, roundingMode});
+    assertEq(nf.format(value), expected, `value=${value}, roundingMode=${roundingMode}`);
+    assertEq(nf.resolvedOptions().roundingMode, roundingMode);
+  }
+}
+
+// Default value is "halfExpand".
+assertEq(new Intl.NumberFormat().resolvedOptions().roundingMode, "halfExpand");
+
+// Invalid values.
+for (let roundingMode of ["", null, "halfOdd", "halfUp", "Up", "up"]){
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("en", {roundingMode}), RangeError);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/rounding-priority.js b/js/src/tests/non262/Intl/NumberFormat/rounding-priority.js
new file mode 100644
index 0000000000..49c9e1b274
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/rounding-priority.js
@@ -0,0 +1,132 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+const tests = [
+  // Rounding conflict with maximum fraction/significand digits.
+  {
+    value: 4.321,
+    options: {
+      maximumFractionDigits: 2,
+      maximumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "4.3",
+      lessPrecision: "4.3",
+      morePrecision: "4.32",
+    },
+  },
+  {
+    value: 4.321,
+    options: {
+      maximumFractionDigits: 2,
+      minimumFractionDigits: 2,
+      maximumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "4.3",
+      lessPrecision: "4.3",
+      morePrecision: "4.32",
+    },
+  },
+  {
+    value: 4.321,
+    options: {
+      maximumFractionDigits: 2,
+      maximumSignificantDigits: 2,
+      minimumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "4.3",
+      lessPrecision: "4.3",
+      morePrecision: "4.32",
+    },
+  },
+  {
+    value: 4.321,
+    options: {
+      maximumFractionDigits: 2,
+      minimumFractionDigits: 2,
+      maximumSignificantDigits: 2,
+      minimumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "4.3",
+      lessPrecision: "4.3",
+      morePrecision: "4.32",
+    },
+  },
+
+  // Rounding conflict with minimum fraction/significand digits.
+  {
+    value: 1.0,
+    options: {
+      minimumFractionDigits: 2,
+      minimumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "1.0",
+      // Returning "1.00" for both options seems unexpected. Also filed at
+      // <https://github.com/tc39/proposal-intl-numberformat-v3/issues/52>.
+      lessPrecision: "1.00",
+      morePrecision: "1.0",
+    },
+  },
+  {
+    value: 1.0,
+    options: {
+      minimumFractionDigits: 2,
+      maximumFractionDigits: 2,
+      minimumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "1.0",
+      lessPrecision: "1.00",
+      morePrecision: "1.0",
+    },
+  },
+  {
+    value: 1.0,
+    options: {
+      minimumFractionDigits: 2,
+      minimumSignificantDigits: 2,
+      maximumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "1.0",
+      lessPrecision: "1.0",
+      morePrecision: "1.00",
+    },
+  },
+  {
+    value: 1.0,
+    options: {
+      minimumFractionDigits: 2,
+      maximumFractionDigits: 2,
+      minimumSignificantDigits: 2,
+      maximumSignificantDigits: 2,
+    },
+    roundingPriorities: {
+      auto: "1.0",
+      lessPrecision: "1.0",
+      morePrecision: "1.00",
+    },
+  },
+];
+
+for (let {value, options, roundingPriorities} of tests) {
+  for (let [roundingPriority, expected] of Object.entries(roundingPriorities)) {
+    let nf = new Intl.NumberFormat("en", {...options, roundingPriority});
+    assertEq(nf.resolvedOptions().roundingPriority, roundingPriority);
+    assertEq(nf.format(value), expected, `value=${value}, roundingPriority=${roundingPriority}`);
+  }
+}
+
+// Default value of "auto".
+assertEq(new Intl.NumberFormat().resolvedOptions().roundingPriority, "auto");
+
+// Invalid values.
+for (let roundingPriority of ["", null, "more", "less", "never"]){
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("en", {roundingPriority}), RangeError);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/shell.js b/js/src/tests/non262/Intl/NumberFormat/shell.js
new file mode 100644
index 0000000000..471fdad71b
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/shell.js
@@ -0,0 +1,77 @@
+function GenericPartCreator(type) {
+    return str => ({ type, value: str });
+}
+
+const NumberFormatParts = {
+    Nan: GenericPartCreator("nan"),
+    Inf: GenericPartCreator("infinity"),
+    Integer: GenericPartCreator("integer"),
+    Group: GenericPartCreator("group"),
+    Decimal: GenericPartCreator("decimal"),
+    Fraction: GenericPartCreator("fraction"),
+    MinusSign: GenericPartCreator("minusSign"),
+    PlusSign: GenericPartCreator("plusSign"),
+    PercentSign: GenericPartCreator("percentSign"),
+    Currency: GenericPartCreator("currency"),
+    Literal: GenericPartCreator("literal"),
+    ExponentSeparator: GenericPartCreator("exponentSeparator"),
+    ExponentMinusSign: GenericPartCreator("exponentMinusSign"),
+    ExponentInteger: GenericPartCreator("exponentInteger"),
+    Compact: GenericPartCreator("compact"),
+    Unit: GenericPartCreator("unit"),
+};
+
+function NumberRangeFormatParts(source) {
+  let entries = Object.entries(NumberFormatParts)
+
+  entries.push(["Approx", GenericPartCreator("approximatelySign")]);
+
+  return Object.fromEntries(entries.map(([key, part]) => {
+    let partWithSource = str => {
+      return Object.defineProperty(part(str), "source", {
+        value: source, writable: true, enumerable: true, configurable: true
+      });
+    };
+    return [key, partWithSource];
+  }));
+}
+
+function assertParts(nf, x, expected) {
+    var parts = nf.formatToParts(x);
+    assertEq(parts.map(part => part.value).join(""), nf.format(x),
+             "formatToParts and format must agree");
+
+    var len = parts.length;
+    assertEq(len, expected.length, "parts count mismatch");
+    for (var i = 0; i < len; i++) {
+        assertEq(parts[i].type, expected[i].type, "type mismatch at " + i);
+        assertEq(parts[i].value, expected[i].value, "value mismatch at " + i);
+    }
+}
+
+function assertRangeParts(nf, start, end, expected) {
+    var parts = nf.formatRangeToParts(start, end);
+    assertEq(parts.map(part => part.value).join(""), nf.formatRange(start, end),
+             "formatRangeToParts and formatRange must agree");
+
+    var len = parts.length;
+    assertEq(len, expected.length, "parts count mismatch");
+    for (var i = 0; i < len; i++) {
+        assertEq(parts[i].type, expected[i].type, "type mismatch at " + i);
+        assertEq(parts[i].value, expected[i].value, "value mismatch at " + i);
+        assertEq(parts[i].source, expected[i].source, "source mismatch at " + i);
+    }
+}
+
+function runNumberFormattingTestcases(testcases) {
+    for (let {locale, options, values} of testcases) {
+        let nf = new Intl.NumberFormat(locale, options);
+
+        for (let {value, string, parts} of values) {
+            assertEq(nf.format(value), string,
+                     `locale=${locale}, options=${JSON.stringify(options)}, value=${value}`);
+
+            assertParts(nf, value, parts);
+        }
+    }
+}
diff --git a/js/src/tests/non262/Intl/NumberFormat/sign-display.js b/js/src/tests/non262/Intl/NumberFormat/sign-display.js
new file mode 100644
index 0000000000..b18517d847
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/sign-display.js
@@ -0,0 +1,187 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Decimal, Fraction
+} = NumberFormatParts;
+
+const testcases = [
+    // "auto": Show the sign on negative numbers only.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "auto",
+        },
+        values: [
+            {value: +0, string: "0", parts: [Integer("0")]},
+            {value: -0, string: "-0", parts: [MinusSign("-"), Integer("0")]},
+            {value: 0n, string: "0", parts: [Integer("0")]},
+
+            {value:   1, string: "1", parts: [Integer("1")]},
+            {value:  -1, string: "-1", parts: [MinusSign("-"), Integer("1")]},
+            {value:  1n, string: "1", parts: [Integer("1")]},
+            {value: -1n, string: "-1", parts: [MinusSign("-"), Integer("1")]},
+
+            {value: 0.1, string: "0.1", parts: [Integer("0"), Decimal("."), Fraction("1")]},
+            {value: -0.1, string: "-0.1", parts: [MinusSign("-"), Integer("0"), Decimal("."), Fraction("1")]},
+
+            {value: 0.9, string: "0.9", parts: [Integer("0"), Decimal("."), Fraction("9")]},
+            {value: -0.9, string: "-0.9", parts: [MinusSign("-"), Integer("0"), Decimal("."), Fraction("9")]},
+
+            {value:  Infinity, string: "∞", parts: [Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // "never": Show the sign on neither positive nor negative numbers.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "never",
+        },
+        values: [
+            {value: +0, string: "0", parts: [Integer("0")]},
+            {value: -0, string: "0", parts: [Integer("0")]},
+            {value: 0n, string: "0", parts: [Integer("0")]},
+
+            {value:   1, string: "1", parts: [Integer("1")]},
+            {value:  -1, string: "1", parts: [Integer("1")]},
+            {value:  1n, string: "1", parts: [Integer("1")]},
+            {value: -1n, string: "1", parts: [Integer("1")]},
+
+            {value: 0.1, string: "0.1", parts: [Integer("0"), Decimal("."), Fraction("1")]},
+            {value: -0.1, string: "0.1", parts: [Integer("0"), Decimal("."), Fraction("1")]},
+
+            {value: 0.9, string: "0.9", parts: [Integer("0"), Decimal("."), Fraction("9")]},
+            {value: -0.9, string: "0.9", parts: [Integer("0"), Decimal("."), Fraction("9")]},
+
+            {value:  Infinity, string: "∞", parts: [Inf("∞")]},
+            {value: -Infinity, string: "∞", parts: [Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // "always": Show the sign on positive and negative numbers including zero.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "always",
+        },
+        values: [
+            {value: +0, string: "+0", parts: [PlusSign("+"), Integer("0")]},
+            {value: -0, string: "-0", parts: [MinusSign("-"), Integer("0")]},
+            {value: 0n, string: "+0", parts: [PlusSign("+"), Integer("0")]},
+
+            {value:   1, string: "+1", parts: [PlusSign("+"), Integer("1")]},
+            {value:  -1, string: "-1", parts: [MinusSign("-"), Integer("1")]},
+            {value:  1n, string: "+1", parts: [PlusSign("+"), Integer("1")]},
+            {value: -1n, string: "-1", parts: [MinusSign("-"), Integer("1")]},
+
+            {value: 0.1, string: "+0.1", parts: [PlusSign("+"), Integer("0"), Decimal("."), Fraction("1")]},
+            {value: -0.1, string: "-0.1", parts: [MinusSign("-"), Integer("0"), Decimal("."), Fraction("1")]},
+
+            {value: 0.9, string: "+0.9", parts: [PlusSign("+"), Integer("0"), Decimal("."), Fraction("9")]},
+            {value: -0.9, string: "-0.9", parts: [MinusSign("-"), Integer("0"), Decimal("."), Fraction("9")]},
+
+            {value:  Infinity, string: "+∞", parts: [PlusSign("+"), Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "+NaN", parts: [PlusSign("+"), Nan("NaN")]},
+            {value: -NaN, string: "+NaN", parts: [PlusSign("+"), Nan("NaN")]},
+        ],
+    },
+
+    // "exceptZero": Show the sign on positive and negative numbers but not zero.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "exceptZero",
+        },
+        values: [
+            {value: +0, string: "0", parts: [Integer("0")]},
+            {value: -0, string: "0", parts: [Integer("0")]},
+            {value: 0n, string: "0", parts: [Integer("0")]},
+
+            {value:   1, string: "+1", parts: [PlusSign("+"), Integer("1")]},
+            {value:  -1, string: "-1", parts: [MinusSign("-"), Integer("1")]},
+            {value:  1n, string: "+1", parts: [PlusSign("+"), Integer("1")]},
+            {value: -1n, string: "-1", parts: [MinusSign("-"), Integer("1")]},
+
+            {value: 0.1, string: "+0.1", parts: [PlusSign("+"), Integer("0"), Decimal("."), Fraction("1")]},
+            {value: -0.1, string: "-0.1", parts: [MinusSign("-"), Integer("0"), Decimal("."), Fraction("1")]},
+
+            {value: 0.9, string: "+0.9", parts: [PlusSign("+"), Integer("0"), Decimal("."), Fraction("9")]},
+            {value: -0.9, string: "-0.9", parts: [MinusSign("-"), Integer("0"), Decimal("."), Fraction("9")]},
+
+            {value:  Infinity, string: "+∞", parts: [PlusSign("+"), Inf("∞")]},
+            {value: -Infinity, string: "-∞", parts: [MinusSign("-"), Inf("∞")]},
+
+            {value:  NaN, string: "NaN", parts: [Nan("NaN")]},
+            {value: -NaN, string: "NaN", parts: [Nan("NaN")]},
+        ],
+    },
+
+    // Tests with suppressed fractional digits.
+
+    // "auto": Show the sign on negative numbers only.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "auto",
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: +0.1, string: "0", parts: [Integer("0")]},
+            {value: -0.1, string: "-0", parts: [MinusSign("-"), Integer("0")]},
+        ],
+    },
+
+    // "never": Show the sign on neither positive nor negative numbers.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "never",
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: +0.1, string: "0", parts: [Integer("0")]},
+            {value: -0.1, string: "0", parts: [Integer("0")]},
+        ],
+    },
+
+    // "always": Show the sign on positive and negative numbers including zero.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "always",
+            maximumFractionDigits: 0,
+        },
+        values: [
+            {value: +0.1, string: "+0", parts: [PlusSign("+"), Integer("0")]},
+            {value: -0.1, string: "-0", parts: [MinusSign("-"), Integer("0")]},
+        ],
+    },
+
+    // "exceptZero": Show the sign on positive and negative numbers but not zero.
+    {
+        locale: "en",
+        options: {
+            signDisplay: "exceptZero",
+            maximumFractionDigits: 0,
+        },
+
+        values: [
+            {value: +0.1, string: "0", parts: [Integer("0")]},
+            {value: -0.1, string: "0", parts: [Integer("0")]},
+        ],
+    }
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/significantDigitsOfZero.js b/js/src/tests/non262/Intl/NumberFormat/significantDigitsOfZero.js
new file mode 100644
index 0000000000..c569313266
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/significantDigitsOfZero.js
@@ -0,0 +1,38 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+// -- test that NumberFormat correctly formats 0 with various numbers of significant digits
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var testData = [
+    {minimumSignificantDigits: 1, maximumSignificantDigits: 1, expected: "0"},
+    {minimumSignificantDigits: 1, maximumSignificantDigits: 2, expected: "0"},
+    {minimumSignificantDigits: 1, maximumSignificantDigits: 3, expected: "0"},
+    {minimumSignificantDigits: 1, maximumSignificantDigits: 4, expected: "0"},
+    {minimumSignificantDigits: 1, maximumSignificantDigits: 5, expected: "0"},
+    {minimumSignificantDigits: 2, maximumSignificantDigits: 2, expected: "0.0"},
+    {minimumSignificantDigits: 2, maximumSignificantDigits: 3, expected: "0.0"},
+    {minimumSignificantDigits: 2, maximumSignificantDigits: 4, expected: "0.0"},
+    {minimumSignificantDigits: 2, maximumSignificantDigits: 5, expected: "0.0"},
+    {minimumSignificantDigits: 3, maximumSignificantDigits: 3, expected: "0.00"},
+    {minimumSignificantDigits: 3, maximumSignificantDigits: 4, expected: "0.00"},
+    {minimumSignificantDigits: 3, maximumSignificantDigits: 5, expected: "0.00"},
+];
+
+for (var i = 0; i < testData.length; i++) {
+    var min = testData[i].minimumSignificantDigits;
+    var max = testData[i].maximumSignificantDigits;
+    var options = {minimumSignificantDigits: min, maximumSignificantDigits: max};
+    var format = new Intl.NumberFormat("en-US", options);
+    var actual = format.format(0);
+    var expected = testData[i].expected;
+    assertEq(actual, expected,
+             "Wrong formatted string for 0 with " +
+             "minimumSignificantDigits " + min +
+             ", maximumSignificantDigits " + max +
+             ": expected \"" + expected +
+             "\", actual \"" + actual + "\"");
+}
+
+reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/supportedLocalesOf.js b/js/src/tests/non262/Intl/NumberFormat/supportedLocalesOf.js
new file mode 100644
index 0000000000..5ba4470a98
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/supportedLocalesOf.js
@@ -0,0 +1,371 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||xulRuntime.shell)
+// -- test in browser only that ICU has locale data for all Mozilla languages
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This array contains the locales that ICU supports in
+// number formatting whose languages Mozilla localizes Firefox into.
+// Current as of ICU 50.1.2 and Firefox March 2013.
+var locales = [
+    "af",
+    "af-NA",
+    "af-ZA",
+    "ar",
+    "ar-001",
+    "ar-AE",
+    "ar-BH",
+    "ar-DJ",
+    "ar-DZ",
+    "ar-EG",
+    "ar-EH",
+    "ar-ER",
+    "ar-IL",
+    "ar-IQ",
+    "ar-JO",
+    "ar-KM",
+    "ar-KW",
+    "ar-LB",
+    "ar-LY",
+    "ar-MA",
+    "ar-MR",
+    "ar-OM",
+    "ar-PS",
+    "ar-QA",
+    "ar-SA",
+    "ar-SD",
+    "ar-SO",
+    "ar-SY",
+    "ar-TD",
+    "ar-TN",
+    "ar-YE",
+    "as",
+    "as-IN",
+    "be",
+    "be-BY",
+    "bg",
+    "bg-BG",
+    "bn",
+    "bn-BD",
+    "bn-IN",
+    "br",
+    "br-FR",
+    "bs",
+    "bs-Cyrl",
+    "bs-Cyrl-BA",
+    "bs-Latn",
+    "bs-Latn-BA",
+    "ca",
+    "ca-AD",
+    "ca-ES",
+    "cs",
+    "cs-CZ",
+    "cy",
+    "cy-GB",
+    "da",
+    "da-DK",
+    "de",
+    "de-AT",
+    "de-BE",
+    "de-CH",
+    "de-DE",
+    "de-LI",
+    "de-LU",
+    "el",
+    "el-CY",
+    "el-GR",
+    "en",
+    "en-150",
+    "en-AG",
+    "en-AS",
+    "en-AU",
+    "en-BB",
+    "en-BE",
+    "en-BM",
+    "en-BS",
+    "en-BW",
+    "en-BZ",
+    "en-CA",
+    "en-CM",
+    "en-DM",
+    "en-FJ",
+    "en-FM",
+    "en-GB",
+    "en-GD",
+    "en-GG",
+    "en-GH",
+    "en-GI",
+    "en-GM",
+    "en-GU",
+    "en-GY",
+    "en-HK",
+    "en-IE",
+    "en-IM",
+    "en-IN",
+    "en-JE",
+    "en-JM",
+    "en-KE",
+    "en-KI",
+    "en-KN",
+    "en-KY",
+    "en-LC",
+    "en-LR",
+    "en-LS",
+    "en-MG",
+    "en-MH",
+    "en-MP",
+    "en-MT",
+    "en-MU",
+    "en-MW",
+    "en-NA",
+    "en-NG",
+    "en-NZ",
+    "en-PG",
+    "en-PH",
+    "en-PK",
+    "en-PR",
+    "en-PW",
+    "en-SB",
+    "en-SC",
+    "en-SG",
+    "en-SL",
+    "en-SS",
+    "en-SZ",
+    "en-TC",
+    "en-TO",
+    "en-TT",
+    "en-TZ",
+    "en-UG",
+    "en-UM",
+    "en-US",
+    "en-US-POSIX",
+    "en-VC",
+    "en-VG",
+    "en-VI",
+    "en-VU",
+    "en-WS",
+    "en-ZA",
+    "en-ZM",
+    "en-ZW",
+    "eo",
+    "es",
+    "es-419",
+    "es-AR",
+    "es-BO",
+    "es-CL",
+    "es-CO",
+    "es-CR",
+    "es-CU",
+    "es-DO",
+    "es-EA",
+    "es-EC",
+    "es-ES",
+    "es-GQ",
+    "es-GT",
+    "es-HN",
+    "es-IC",
+    "es-MX",
+    "es-NI",
+    "es-PA",
+    "es-PE",
+    "es-PH",
+    "es-PR",
+    "es-PY",
+    "es-SV",
+    "es-US",
+    "es-UY",
+    "es-VE",
+    "et",
+    "et-EE",
+    "eu",
+    "eu-ES",
+    "fa",
+    "fa-AF",
+    "fa-IR",
+    "ff",
+    "ff-SN",
+    "fi",
+    "fi-FI",
+    "fr",
+    "fr-BE",
+    "fr-BF",
+    "fr-BI",
+    "fr-BJ",
+    "fr-BL",
+    "fr-CA",
+    "fr-CD",
+    "fr-CF",
+    "fr-CG",
+    "fr-CH",
+    "fr-CI",
+    "fr-CM",
+    "fr-DJ",
+    "fr-DZ",
+    "fr-FR",
+    "fr-GA",
+    "fr-GF",
+    "fr-GN",
+    "fr-GP",
+    "fr-GQ",
+    "fr-HT",
+    "fr-KM",
+    "fr-LU",
+    "fr-MA",
+    "fr-MC",
+    "fr-MF",
+    "fr-MG",
+    "fr-ML",
+    "fr-MQ",
+    "fr-MR",
+    "fr-MU",
+    "fr-NC",
+    "fr-NE",
+    "fr-PF",
+    "fr-RE",
+    "fr-RW",
+    "fr-SC",
+    "fr-SN",
+    "fr-SY",
+    "fr-TD",
+    "fr-TG",
+    "fr-TN",
+    "fr-VU",
+    "fr-YT",
+    "ga",
+    "ga-IE",
+    "gl",
+    "gl-ES",
+    "gu",
+    "gu-IN",
+    "he",
+    "he-IL",
+    "hi",
+    "hi-IN",
+    "hr",
+    "hr-BA",
+    "hr-HR",
+    "hu",
+    "hu-HU",
+    "hy",
+    "hy-AM",
+    "id",
+    "id-ID",
+    "is",
+    "is-IS",
+    "it",
+    "it-CH",
+    "it-IT",
+    "it-SM",
+    "ja",
+    "ja-JP",
+    "kk",
+    "kk-Cyrl",
+    "kk-Cyrl-KZ",
+    "km",
+    "km-KH",
+    "kn",
+    "kn-IN",
+    "ko",
+    "ko-KP",
+    "ko-KR",
+    "lt",
+    "lt-LT",
+    "lv",
+    "lv-LV",
+    "mk",
+    "mk-MK",
+    "ml",
+    "ml-IN",
+    "mr",
+    "mr-IN",
+    "nb",
+    "nb-NO",
+    "nl",
+    "nl-AW",
+    "nl-BE",
+    "nl-CW",
+    "nl-NL",
+    "nl-SR",
+    "nl-SX",
+    "nn",
+    "nn-NO",
+    "or",
+    "or-IN",
+    "pa",
+    "pa-Arab",
+    "pa-Arab-PK",
+    "pa-Guru",
+    "pa-Guru-IN",
+    "pl",
+    "pl-PL",
+    "pt",
+    "pt-AO",
+    "pt-BR",
+    "pt-CV",
+    "pt-GW",
+    "pt-MO",
+    "pt-MZ",
+    "pt-PT",
+    "pt-ST",
+    "pt-TL",
+    "rm",
+    "rm-CH",
+    "ro",
+    "ro-MD",
+    "ro-RO",
+    "ru",
+    "ru-BY",
+    "ru-KG",
+    "ru-KZ",
+    "ru-MD",
+    "ru-RU",
+    "ru-UA",
+    "si",
+    "si-LK",
+    "sk",
+    "sk-SK",
+    "sl",
+    "sl-SI",
+    "sq",
+    "sq-AL",
+    "sq-MK",
+    "sr",
+    "sr-Cyrl",
+    "sr-Cyrl-BA",
+    "sr-Cyrl-ME",
+    "sr-Cyrl-RS",
+    "sr-Latn",
+    "sr-Latn-BA",
+    "sr-Latn-ME",
+    "sr-Latn-RS",
+    "sv",
+    "sv-AX",
+    "sv-FI",
+    "sv-SE",
+    "te",
+    "te-IN",
+    "th",
+    "th-TH",
+    "tr",
+    "tr-CY",
+    "tr-TR",
+    "uk",
+    "uk-UA",
+    "vi",
+    "vi-VN",
+    "zh",
+    "zh-Hans",
+    "zh-Hans-CN",
+    "zh-Hans-HK",
+    "zh-Hans-MO",
+    "zh-Hans-SG",
+    "zh-Hant",
+    "zh-Hant-HK",
+    "zh-Hant-MO",
+    "zh-Hant-TW",
+];
+
+var count = Intl.NumberFormat.supportedLocalesOf(locales).length;
+
+reportCompare(locales.length, count, "Number of supported locales in Intl.NumberFormat");
diff --git a/js/src/tests/non262/Intl/NumberFormat/toStringTag.js b/js/src/tests/non262/Intl/NumberFormat/toStringTag.js
new file mode 100644
index 0000000000..9ad0901a0b
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/toStringTag.js
@@ -0,0 +1,29 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var desc = Object.getOwnPropertyDescriptor(Intl.NumberFormat.prototype, Symbol.toStringTag);
+
+assertEq(desc !== undefined, true);
+assertEq(desc.value, "Intl.NumberFormat");
+assertEq(desc.writable, false);
+assertEq(desc.enumerable, false);
+assertEq(desc.configurable, true);
+
+assertEq(Object.prototype.toString.call(Intl.NumberFormat.prototype), "[object Intl.NumberFormat]");
+assertEq(Object.prototype.toString.call(new Intl.NumberFormat), "[object Intl.NumberFormat]");
+
+Object.defineProperty(Intl.NumberFormat.prototype, Symbol.toStringTag, {value: "NumberFormat"});
+
+assertEq(Object.prototype.toString.call(Intl.NumberFormat.prototype), "[object NumberFormat]");
+assertEq(Object.prototype.toString.call(new Intl.NumberFormat), "[object NumberFormat]");
+
+delete Intl.NumberFormat.prototype[Symbol.toStringTag];
+
+assertEq(Object.prototype.toString.call(Intl.NumberFormat.prototype), "[object Object]");
+assertEq(Object.prototype.toString.call(new Intl.NumberFormat), "[object Object]");
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/trailing-zero-display.js b/js/src/tests/non262/Intl/NumberFormat/trailing-zero-display.js
new file mode 100644
index 0000000000..5e3113285a
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/trailing-zero-display.js
@@ -0,0 +1,98 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+// "stripIfInteger" with fractional digits.
+{
+  let nf1 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+  });
+
+  let nf2 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    trailingZeroDisplay: "auto",
+  });
+
+  let nf3 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    trailingZeroDisplay: "stripIfInteger",
+  });
+
+  assertEq(nf1.resolvedOptions().trailingZeroDisplay, "auto");
+  assertEq(nf2.resolvedOptions().trailingZeroDisplay, "auto");
+  assertEq(nf3.resolvedOptions().trailingZeroDisplay, "stripIfInteger");
+
+  assertEq(nf1.format(123), "123.00");
+  assertEq(nf2.format(123), "123.00");
+  assertEq(nf3.format(123), "123");
+}
+
+// "stripIfInteger" with significand digits.
+{
+  let nf1 = new Intl.NumberFormat("en", {
+    minimumSignificantDigits: 2,
+  });
+
+  let nf2 = new Intl.NumberFormat("en", {
+    minimumSignificantDigits: 2,
+    trailingZeroDisplay: "auto",
+  });
+
+  let nf3 = new Intl.NumberFormat("en", {
+    minimumSignificantDigits: 2,
+    trailingZeroDisplay: "stripIfInteger",
+  });
+
+  assertEq(nf1.resolvedOptions().trailingZeroDisplay, "auto");
+  assertEq(nf2.resolvedOptions().trailingZeroDisplay, "auto");
+  assertEq(nf3.resolvedOptions().trailingZeroDisplay, "stripIfInteger");
+
+  assertEq(nf1.format(1), "1.0");
+  assertEq(nf2.format(1), "1.0");
+  assertEq(nf3.format(1), "1");
+}
+
+// "stripIfInteger" with rounding increment.
+{
+  let nf1 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+    roundingIncrement: 5,
+  });
+  let nf2 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+    roundingIncrement: 5,
+    trailingZeroDisplay: "auto",
+  });
+  let nf3 = new Intl.NumberFormat("en", {
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+    roundingIncrement: 5,
+    trailingZeroDisplay: "stripIfInteger",
+  });
+
+  assertEq(nf1.resolvedOptions().trailingZeroDisplay, "auto");
+  assertEq(nf2.resolvedOptions().trailingZeroDisplay, "auto");
+  assertEq(nf3.resolvedOptions().trailingZeroDisplay, "stripIfInteger");
+
+  // NB: Tests 1.975 twice b/c of <https://unicode-org.atlassian.net/browse/ICU-21674>.
+
+  assertEq(nf1.format(1.975), "2.00");
+  assertEq(nf1.format(1.97), "1.95");
+  assertEq(nf1.format(1.975), "2.00");
+
+  assertEq(nf2.format(1.975), "2.00");
+  assertEq(nf2.format(1.97), "1.95");
+  assertEq(nf2.format(1.975), "2.00");
+
+  assertEq(nf3.format(1.975), "2");
+  assertEq(nf3.format(1.97), "1.95");
+  assertEq(nf3.format(1.975), "2");
+}
+
+// Invalid values.
+for (let trailingZeroDisplay of ["", "true", true, "none", "yes", "no"]){
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("en", {trailingZeroDisplay}), RangeError);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/unit-compound-combinations.js b/js/src/tests/non262/Intl/NumberFormat/unit-compound-combinations.js
new file mode 100644
index 0000000000..2aad94b98e
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/unit-compound-combinations.js
@@ -0,0 +1,65 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Generated by make_intl_data.py. DO NOT EDIT.
+
+const sanctionedSimpleUnitIdentifiers = [
+    "acre",
+    "bit",
+    "byte",
+    "celsius",
+    "centimeter",
+    "day",
+    "degree",
+    "fahrenheit",
+    "fluid-ounce",
+    "foot",
+    "gallon",
+    "gigabit",
+    "gigabyte",
+    "gram",
+    "hectare",
+    "hour",
+    "inch",
+    "kilobit",
+    "kilobyte",
+    "kilogram",
+    "kilometer",
+    "liter",
+    "megabit",
+    "megabyte",
+    "meter",
+    "microsecond",
+    "mile",
+    "mile-scandinavian",
+    "milliliter",
+    "millimeter",
+    "millisecond",
+    "minute",
+    "month",
+    "nanosecond",
+    "ounce",
+    "percent",
+    "petabyte",
+    "pound",
+    "second",
+    "stone",
+    "terabit",
+    "terabyte",
+    "week",
+    "yard",
+    "year"
+];
+
+// Test all simple unit identifier combinations are allowed.
+
+for (const numerator of sanctionedSimpleUnitIdentifiers) {
+    for (const denominator of sanctionedSimpleUnitIdentifiers) {
+        const unit = `${numerator}-per-${denominator}`;
+        const nf = new Intl.NumberFormat("en", {style: "unit", unit});
+
+        assertEq(nf.format(1), nf.formatToParts(1).map(p => p.value).join(""));
+    }
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/unit-formatToParts-has-unit-field.js b/js/src/tests/non262/Intl/NumberFormat/unit-formatToParts-has-unit-field.js
new file mode 100644
index 0000000000..9292c8ac73
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/unit-formatToParts-has-unit-field.js
@@ -0,0 +1,90 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Generated by make_intl_data.py. DO NOT EDIT.
+
+const sanctionedSimpleUnitIdentifiers = [
+  "acre",
+  "bit",
+  "byte",
+  "celsius",
+  "centimeter",
+  "day",
+  "degree",
+  "fahrenheit",
+  "fluid-ounce",
+  "foot",
+  "gallon",
+  "gigabit",
+  "gigabyte",
+  "gram",
+  "hectare",
+  "hour",
+  "inch",
+  "kilobit",
+  "kilobyte",
+  "kilogram",
+  "kilometer",
+  "liter",
+  "megabit",
+  "megabyte",
+  "meter",
+  "microsecond",
+  "mile",
+  "mile-scandinavian",
+  "milliliter",
+  "millimeter",
+  "millisecond",
+  "minute",
+  "month",
+  "nanosecond",
+  "ounce",
+  "percent",
+  "petabyte",
+  "pound",
+  "second",
+  "stone",
+  "terabit",
+  "terabyte",
+  "week",
+  "yard",
+  "year"
+];
+
+// Test only English and Chinese to keep the overall runtime reasonable.
+//
+// Chinese is included because it contains more than one "unit" element for
+// certain unit combinations.
+const locales = ["en", "zh"];
+
+// Plural rules for English only differentiate between "one" and "other". Plural
+// rules for Chinese only use "other". That means we only need to test two values
+// per unit.
+const values = [0, 1];
+
+// Ensure unit formatters contain at least one "unit" element.
+
+for (const locale of locales) {
+  for (const unit of sanctionedSimpleUnitIdentifiers) {
+    const nf = new Intl.NumberFormat(locale, {style: "unit", unit});
+
+    for (const value of values) {
+      assertEq(nf.formatToParts(value).some(e => e.type === "unit"), true,
+               `locale=${locale}, unit=${unit}`);
+    }
+  }
+
+  for (const numerator of sanctionedSimpleUnitIdentifiers) {
+    for (const denominator of sanctionedSimpleUnitIdentifiers) {
+      const unit = `${numerator}-per-${denominator}`;
+      const nf = new Intl.NumberFormat(locale, {style: "unit", unit});
+
+      for (const value of values) {
+        assertEq(nf.formatToParts(value).some(e => e.type === "unit"), true,
+                 `locale=${locale}, unit=${unit}`);
+      }
+    }
+  }
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/unit-well-formed.js b/js/src/tests/non262/Intl/NumberFormat/unit-well-formed.js
new file mode 100644
index 0000000000..8eca3b58cf
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/unit-well-formed.js
@@ -0,0 +1,267 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Generated by make_intl_data.py. DO NOT EDIT.
+
+const sanctionedSimpleUnitIdentifiers = [
+    "acre",
+    "bit",
+    "byte",
+    "celsius",
+    "centimeter",
+    "day",
+    "degree",
+    "fahrenheit",
+    "fluid-ounce",
+    "foot",
+    "gallon",
+    "gigabit",
+    "gigabyte",
+    "gram",
+    "hectare",
+    "hour",
+    "inch",
+    "kilobit",
+    "kilobyte",
+    "kilogram",
+    "kilometer",
+    "liter",
+    "megabit",
+    "megabyte",
+    "meter",
+    "microsecond",
+    "mile",
+    "mile-scandinavian",
+    "milliliter",
+    "millimeter",
+    "millisecond",
+    "minute",
+    "month",
+    "nanosecond",
+    "ounce",
+    "percent",
+    "petabyte",
+    "pound",
+    "second",
+    "stone",
+    "terabit",
+    "terabyte",
+    "week",
+    "yard",
+    "year"
+];
+
+const allUnits = [
+    "acceleration-g-force",
+    "acceleration-meter-per-square-second",
+    "angle-arc-minute",
+    "angle-arc-second",
+    "angle-degree",
+    "angle-radian",
+    "angle-revolution",
+    "area-acre",
+    "area-dunam",
+    "area-hectare",
+    "area-square-centimeter",
+    "area-square-foot",
+    "area-square-inch",
+    "area-square-kilometer",
+    "area-square-meter",
+    "area-square-mile",
+    "area-square-yard",
+    "concentr-item",
+    "concentr-karat",
+    "concentr-milligram-ofglucose-per-deciliter",
+    "concentr-millimole-per-liter",
+    "concentr-mole",
+    "concentr-percent",
+    "concentr-permille",
+    "concentr-permillion",
+    "concentr-permyriad",
+    "consumption-liter-per-100-kilometer",
+    "consumption-liter-per-kilometer",
+    "consumption-mile-per-gallon",
+    "consumption-mile-per-gallon-imperial",
+    "digital-bit",
+    "digital-byte",
+    "digital-gigabit",
+    "digital-gigabyte",
+    "digital-kilobit",
+    "digital-kilobyte",
+    "digital-megabit",
+    "digital-megabyte",
+    "digital-petabyte",
+    "digital-terabit",
+    "digital-terabyte",
+    "duration-century",
+    "duration-day",
+    "duration-day-person",
+    "duration-decade",
+    "duration-hour",
+    "duration-microsecond",
+    "duration-millisecond",
+    "duration-minute",
+    "duration-month",
+    "duration-month-person",
+    "duration-nanosecond",
+    "duration-quarter",
+    "duration-second",
+    "duration-week",
+    "duration-week-person",
+    "duration-year",
+    "duration-year-person",
+    "electric-ampere",
+    "electric-milliampere",
+    "electric-ohm",
+    "electric-volt",
+    "energy-british-thermal-unit",
+    "energy-calorie",
+    "energy-electronvolt",
+    "energy-foodcalorie",
+    "energy-joule",
+    "energy-kilocalorie",
+    "energy-kilojoule",
+    "energy-kilowatt-hour",
+    "energy-therm-us",
+    "force-kilowatt-hour-per-100-kilometer",
+    "force-newton",
+    "force-pound-force",
+    "frequency-gigahertz",
+    "frequency-hertz",
+    "frequency-kilohertz",
+    "frequency-megahertz",
+    "graphics-dot",
+    "graphics-dot-per-centimeter",
+    "graphics-dot-per-inch",
+    "graphics-em",
+    "graphics-megapixel",
+    "graphics-pixel",
+    "graphics-pixel-per-centimeter",
+    "graphics-pixel-per-inch",
+    "length-astronomical-unit",
+    "length-centimeter",
+    "length-decimeter",
+    "length-earth-radius",
+    "length-fathom",
+    "length-foot",
+    "length-furlong",
+    "length-inch",
+    "length-kilometer",
+    "length-light-year",
+    "length-meter",
+    "length-micrometer",
+    "length-mile",
+    "length-mile-scandinavian",
+    "length-millimeter",
+    "length-nanometer",
+    "length-nautical-mile",
+    "length-parsec",
+    "length-picometer",
+    "length-point",
+    "length-solar-radius",
+    "length-yard",
+    "light-candela",
+    "light-lumen",
+    "light-lux",
+    "light-solar-luminosity",
+    "mass-carat",
+    "mass-dalton",
+    "mass-earth-mass",
+    "mass-grain",
+    "mass-gram",
+    "mass-kilogram",
+    "mass-microgram",
+    "mass-milligram",
+    "mass-ounce",
+    "mass-ounce-troy",
+    "mass-pound",
+    "mass-solar-mass",
+    "mass-stone",
+    "mass-ton",
+    "mass-tonne",
+    "power-gigawatt",
+    "power-horsepower",
+    "power-kilowatt",
+    "power-megawatt",
+    "power-milliwatt",
+    "power-watt",
+    "pressure-atmosphere",
+    "pressure-bar",
+    "pressure-hectopascal",
+    "pressure-inch-ofhg",
+    "pressure-kilopascal",
+    "pressure-megapascal",
+    "pressure-millibar",
+    "pressure-millimeter-ofhg",
+    "pressure-pascal",
+    "pressure-pound-force-per-square-inch",
+    "speed-kilometer-per-hour",
+    "speed-knot",
+    "speed-meter-per-second",
+    "speed-mile-per-hour",
+    "temperature-celsius",
+    "temperature-fahrenheit",
+    "temperature-generic",
+    "temperature-kelvin",
+    "torque-newton-meter",
+    "torque-pound-force-foot",
+    "volume-acre-foot",
+    "volume-barrel",
+    "volume-bushel",
+    "volume-centiliter",
+    "volume-cubic-centimeter",
+    "volume-cubic-foot",
+    "volume-cubic-inch",
+    "volume-cubic-kilometer",
+    "volume-cubic-meter",
+    "volume-cubic-mile",
+    "volume-cubic-yard",
+    "volume-cup",
+    "volume-cup-metric",
+    "volume-deciliter",
+    "volume-dessert-spoon",
+    "volume-dessert-spoon-imperial",
+    "volume-dram",
+    "volume-drop",
+    "volume-fluid-ounce",
+    "volume-fluid-ounce-imperial",
+    "volume-gallon",
+    "volume-gallon-imperial",
+    "volume-hectoliter",
+    "volume-jigger",
+    "volume-liter",
+    "volume-megaliter",
+    "volume-milliliter",
+    "volume-pinch",
+    "volume-pint",
+    "volume-pint-metric",
+    "volume-quart",
+    "volume-quart-imperial",
+    "volume-tablespoon",
+    "volume-teaspoon"
+];
+
+// Test only sanctioned unit identifiers are allowed.
+
+for (const typeAndUnit of allUnits) {
+    const [_, type, unit] = typeAndUnit.match(/(\w+)-(.+)/);
+
+    let allowed;
+    if (unit.includes("-per-")) {
+        const [numerator, denominator] = unit.split("-per-");
+        allowed = sanctionedSimpleUnitIdentifiers.includes(numerator) &&
+                  sanctionedSimpleUnitIdentifiers.includes(denominator);
+    } else {
+        allowed = sanctionedSimpleUnitIdentifiers.includes(unit);
+    }
+
+    if (allowed) {
+        const nf = new Intl.NumberFormat("en", {style: "unit", unit});
+        assertEq(nf.format(1), nf.formatToParts(1).map(p => p.value).join(""));
+    } else {
+        assertThrowsInstanceOf(() => new Intl.NumberFormat("en", {style: "unit", unit}),
+                               RangeError, `Missing error for "${typeAndUnit}"`);
+    }
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/unit.js b/js/src/tests/non262/Intl/NumberFormat/unit.js
new file mode 100644
index 0000000000..7abc5142e0
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/unit.js
@@ -0,0 +1,104 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+const {
+    Nan, Inf, Integer, MinusSign, PlusSign, Literal,
+    Unit
+} = NumberFormatParts;
+
+const testcases = [
+    {
+        locale: "en",
+        options: {
+            style: "unit",
+            unit: "meter",
+            unitDisplay: "short",
+        },
+        values: [
+            {value: +0, string: "0 m", parts: [Integer("0"), Literal(" "), Unit("m")]},
+            {value: -0, string: "-0 m", parts: [MinusSign("-"), Integer("0"), Literal(" "), Unit("m")]},
+            {value: 0n, string: "0 m", parts: [Integer("0"), Literal(" "), Unit("m")]},
+
+            {value:   1, string: "1 m", parts: [Integer("1"), Literal(" "), Unit("m")]},
+            {value:  -1, string: "-1 m", parts: [MinusSign("-"), Integer("1"), Literal(" "), Unit("m")]},
+            {value:  1n, string: "1 m", parts: [Integer("1"), Literal(" "), Unit("m")]},
+            {value: -1n, string: "-1 m", parts: [MinusSign("-"), Integer("1"), Literal(" "), Unit("m")]},
+
+            {value:  Infinity, string: "∞ m", parts: [Inf("∞"), Literal(" "), Unit("m")]},
+            {value: -Infinity, string: "-∞ m", parts: [MinusSign("-"), Inf("∞"), Literal(" "), Unit("m")]},
+
+            {value:  NaN, string: "NaN m", parts: [Nan("NaN"), Literal(" "), Unit("m")]},
+            {value: -NaN, string: "NaN m", parts: [Nan("NaN"), Literal(" "), Unit("m")]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            style: "unit",
+            unit: "meter",
+            unitDisplay: "narrow",
+        },
+        values: [
+            {value: +0, string: "0m", parts: [Integer("0"), Unit("m")]},
+            {value: -0, string: "-0m", parts: [MinusSign("-"), Integer("0"), Unit("m")]},
+            {value: 0n, string: "0m", parts: [Integer("0"), Unit("m")]},
+
+            {value:   1, string: "1m", parts: [Integer("1"), Unit("m")]},
+            {value:  -1, string: "-1m", parts: [MinusSign("-"), Integer("1"), Unit("m")]},
+            {value:  1n, string: "1m", parts: [Integer("1"), Unit("m")]},
+            {value: -1n, string: "-1m", parts: [MinusSign("-"), Integer("1"), Unit("m")]},
+
+            {value:  Infinity, string: "∞m", parts: [Inf("∞"), Unit("m")]},
+            {value: -Infinity, string: "-∞m", parts: [MinusSign("-"), Inf("∞"), Unit("m")]},
+
+            {value:  NaN, string: "NaNm", parts: [Nan("NaN"), Unit("m")]},
+            {value: -NaN, string: "NaNm", parts: [Nan("NaN"), Unit("m")]},
+        ],
+    },
+
+    {
+        locale: "en",
+        options: {
+            style: "unit",
+            unit: "meter",
+            unitDisplay: "long",
+        },
+        values: [
+            {value: +0, string: "0 meters", parts: [Integer("0"), Literal(" "), Unit("meters")]},
+            {value: -0, string: "-0 meters", parts: [MinusSign("-"), Integer("0"), Literal(" "), Unit("meters")]},
+            {value: 0n, string: "0 meters", parts: [Integer("0"), Literal(" "), Unit("meters")]},
+
+            {value:   1, string: "1 meter", parts: [Integer("1"), Literal(" "), Unit("meter")]},
+            {value:  -1, string: "-1 meter", parts: [MinusSign("-"), Integer("1"), Literal(" "), Unit("meter")]},
+            {value:  1n, string: "1 meter", parts: [Integer("1"), Literal(" "), Unit("meter")]},
+            {value: -1n, string: "-1 meter", parts: [MinusSign("-"), Integer("1"), Literal(" "), Unit("meter")]},
+
+            {value:  Infinity, string: "∞ meters", parts: [Inf("∞"), Literal(" "), Unit("meters")]},
+            {value: -Infinity, string: "-∞ meters", parts: [MinusSign("-"), Inf("∞"), Literal(" "), Unit("meters")]},
+
+            {value:  NaN, string: "NaN meters", parts: [Nan("NaN"), Literal(" "), Unit("meters")]},
+            {value: -NaN, string: "NaN meters", parts: [Nan("NaN"), Literal(" "), Unit("meters")]},
+        ],
+    },
+
+    // Ensure the correct compound unit is automatically selected by ICU. For
+    // example instead of "50 chilometri al orari", 50 km/h should return
+    // "50 chilometri orari" in Italian.
+
+    {
+        locale: "it",
+        options: {
+            style: "unit",
+            unit: "kilometer-per-hour",
+            unitDisplay: "long",
+        },
+        values: [
+            {value: 50, string: "50 chilometri orari", parts: [Integer("50"), Literal(" "), Unit("chilometri orari")]},
+        ],
+    },
+];
+
+runNumberFormattingTestcases(testcases);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/unwrapping.js b/js/src/tests/non262/Intl/NumberFormat/unwrapping.js
new file mode 100644
index 0000000000..df0b15d6fc
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/unwrapping.js
@@ -0,0 +1,248 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Test UnwrapNumberFormat operation.
+
+const numberFormatFunctions = [];
+numberFormatFunctions.push({
+    function: Intl.NumberFormat.prototype.resolvedOptions,
+    unwrap: true,
+});
+numberFormatFunctions.push({
+    function: Object.getOwnPropertyDescriptor(Intl.NumberFormat.prototype, "format").get,
+    unwrap: true,
+});
+numberFormatFunctions.push({
+    function: Intl.NumberFormat.prototype.formatToParts,
+    unwrap: false,
+});
+
+function IsIntlService(c) {
+    return typeof c === "function" &&
+           c.hasOwnProperty("prototype") &&
+           c.prototype.hasOwnProperty("resolvedOptions");
+}
+
+function IsObject(o) {
+    return Object(o) === o;
+}
+
+function IsPrimitive(o) {
+    return Object(o) !== o;
+}
+
+function intlObjects(ctor) {
+    let args = [];
+    if (ctor === Intl.DisplayNames) {
+        // Intl.DisplayNames can't be constructed without any arguments.
+        args = [undefined, {type: "language"}];
+    }
+
+    return [
+        // Instance of an Intl constructor.
+        new ctor(...args),
+
+        // Instance of a subclassed Intl constructor.
+        new class extends ctor {}(...args),
+
+        // Intl object not inheriting from its default prototype.
+        Object.setPrototypeOf(new ctor(...args), Object.prototype),
+    ];
+}
+
+function thisValues(C) {
+    const intlConstructors = Object.getOwnPropertyNames(Intl).map(name => Intl[name]).filter(IsIntlService);
+
+    return [
+        // Primitive values.
+        ...[undefined, null, true, "abc", Symbol(), 123],
+
+        // Object values.
+        ...[{}, [], /(?:)/, function(){}, new Proxy({}, {})],
+
+        // Intl objects.
+        ...[].concat(...intlConstructors.filter(ctor => ctor !== C).map(intlObjects)),
+
+        // Object inheriting from an Intl constructor prototype.
+        ...intlConstructors.map(ctor => Object.create(ctor.prototype)),
+    ];
+}
+
+const intlFallbackSymbol = Object.getOwnPropertySymbols(Intl.NumberFormat.call(Object.create(Intl.NumberFormat.prototype)))[0];
+
+// Test Intl.NumberFormat.prototype methods.
+for (let {function: numberFormatFunction, unwrap} of numberFormatFunctions) {
+    // Test a TypeError is thrown when the this-value isn't an initialized
+    // Intl.NumberFormat instance.
+    for (let thisValue of thisValues(Intl.NumberFormat)) {
+        assertThrowsInstanceOf(() => numberFormatFunction.call(thisValue), TypeError);
+    }
+
+    // And test no error is thrown for initialized Intl.NumberFormat instances.
+    for (let thisValue of intlObjects(Intl.NumberFormat)) {
+        numberFormatFunction.call(thisValue);
+    }
+
+    // Manually add [[FallbackSymbol]] to objects and then repeat the tests from above.
+    for (let thisValue of thisValues(Intl.NumberFormat)) {
+        assertThrowsInstanceOf(() => numberFormatFunction.call({
+            __proto__: Intl.NumberFormat.prototype,
+            [intlFallbackSymbol]: thisValue,
+        }), TypeError);
+    }
+
+    for (let thisValue of intlObjects(Intl.NumberFormat)) {
+        let obj = {
+            __proto__: Intl.NumberFormat.prototype,
+            [intlFallbackSymbol]: thisValue,
+        };
+        if (unwrap) {
+            numberFormatFunction.call(obj);
+        } else {
+            assertThrowsInstanceOf(() => numberFormatFunction.call(obj), TypeError);
+        }
+    }
+
+    // Ensure [[FallbackSymbol]] isn't retrieved for Intl.NumberFormat instances.
+    for (let thisValue of intlObjects(Intl.NumberFormat)) {
+        Object.defineProperty(thisValue, intlFallbackSymbol, {
+            get() { assertEq(false, true); }
+        });
+        numberFormatFunction.call(thisValue);
+    }
+
+    // Ensure [[FallbackSymbol]] is only retrieved for objects inheriting from Intl.NumberFormat.prototype.
+    for (let thisValue of thisValues(Intl.NumberFormat).filter(IsObject)) {
+        if (Intl.NumberFormat.prototype.isPrototypeOf(thisValue))
+            continue;
+        Object.defineProperty(thisValue, intlFallbackSymbol, {
+            get() { assertEq(false, true); }
+        });
+        assertThrowsInstanceOf(() => numberFormatFunction.call(thisValue), TypeError);
+    }
+
+    // Repeat the test from above, but also change Intl.NumberFormat[@@hasInstance]
+    // so it always returns |true|.
+    for (let thisValue of thisValues(Intl.NumberFormat).filter(IsObject)) {
+        let isPrototypeOf = Intl.NumberFormat.prototype.isPrototypeOf(thisValue);
+        let hasInstanceCalled = false, symbolGetterCalled = false;
+        Object.defineProperty(Intl.NumberFormat, Symbol.hasInstance, {
+            value() {
+                assertEq(hasInstanceCalled, false);
+                hasInstanceCalled = true;
+                return true;
+            }, configurable: true
+        });
+        Object.defineProperty(thisValue, intlFallbackSymbol, {
+            get() {
+                assertEq(symbolGetterCalled, false);
+                symbolGetterCalled = true;
+                return null;
+            }, configurable: true
+        });
+
+        assertThrowsInstanceOf(() => numberFormatFunction.call(thisValue), TypeError);
+
+        delete Intl.NumberFormat[Symbol.hasInstance];
+
+        assertEq(hasInstanceCalled, false);
+        assertEq(symbolGetterCalled, unwrap && isPrototypeOf);
+    }
+
+    // Test with primitive values.
+    for (let thisValue of thisValues(Intl.NumberFormat).filter(IsPrimitive)) {
+        // Ensure @@hasInstance is not called.
+        Object.defineProperty(Intl.NumberFormat, Symbol.hasInstance, {
+            value() { assertEq(true, false); }, configurable: true
+        });
+        let isUndefinedOrNull = thisValue === undefined || thisValue === null;
+        let symbolHolder;
+        if (!isUndefinedOrNull) {
+            // Ensure the fallback symbol isn't retrieved from the primitive wrapper prototype.
+            symbolHolder = Object.getPrototypeOf(thisValue);
+            Object.defineProperty(symbolHolder, intlFallbackSymbol, {
+                get() { assertEq(true, false); }, configurable: true
+            });
+        }
+
+        assertThrowsInstanceOf(() => numberFormatFunction.call(thisValue), TypeError);
+
+        delete Intl.NumberFormat[Symbol.hasInstance];
+        if (!isUndefinedOrNull)
+            delete symbolHolder[intlFallbackSymbol];
+    }
+}
+
+// Test format() returns the correct result for objects initialized as Intl.NumberFormat instances.
+{
+    // An actual Intl.NumberFormat instance.
+    let numberFormat = new Intl.NumberFormat();
+
+    // An object initialized as a NumberFormat instance.
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    Intl.NumberFormat.call(thisValue);
+
+    // Object with [[FallbackSymbol]] set to NumberFormat instance.
+    let fakeObj = {
+        __proto__: Intl.NumberFormat.prototype,
+        [intlFallbackSymbol]: numberFormat,
+    };
+
+    for (let number of [0, 1, 1.5, Infinity, NaN]) {
+        let expected = numberFormat.format(number);
+        assertEq(thisValue.format(number), expected);
+        assertEq(thisValue[intlFallbackSymbol].format(number), expected);
+        assertEq(fakeObj.format(number), expected);
+    }
+}
+
+// Ensure formatToParts() doesn't use the fallback semantics.
+{
+    let formatToParts = Intl.NumberFormat.prototype.formatToParts;
+
+    // An object initialized as a NumberFormat instance.
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    Intl.NumberFormat.call(thisValue);
+    assertThrowsInstanceOf(() => formatToParts.call(thisValue), TypeError);
+
+    // Object with [[FallbackSymbol]] set to NumberFormat instance.
+    let fakeObj = {
+        __proto__: Intl.NumberFormat.prototype,
+        [intlFallbackSymbol]: new Intl.NumberFormat(),
+    };
+    assertThrowsInstanceOf(() => formatToParts.call(fakeObj), TypeError);
+}
+
+// Test resolvedOptions() returns the same results.
+{
+    // An actual Intl.NumberFormat instance.
+    let numberFormat = new Intl.NumberFormat();
+
+    // An object initialized as a NumberFormat instance.
+    let thisValue = Object.create(Intl.NumberFormat.prototype);
+    Intl.NumberFormat.call(thisValue);
+
+    // Object with [[FallbackSymbol]] set to NumberFormat instance.
+    let fakeObj = {
+        __proto__: Intl.NumberFormat.prototype,
+        [intlFallbackSymbol]: numberFormat,
+    };
+
+    function assertEqOptions(actual, expected) {
+        actual = Object.entries(actual);
+        expected = Object.entries(expected);
+
+        assertEq(actual.length, expected.length, "options count mismatch");
+        for (var i = 0; i < expected.length; i++) {
+            assertEq(actual[i][0], expected[i][0], "key mismatch at " + i);
+            assertEq(actual[i][1], expected[i][1], "value mismatch at " + i);
+        }
+    }
+
+    let expected = numberFormat.resolvedOptions();
+    assertEqOptions(thisValue.resolvedOptions(), expected);
+    assertEqOptions(thisValue[intlFallbackSymbol].resolvedOptions(), expected);
+    assertEqOptions(fakeObj.resolvedOptions(), expected);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/use-grouping-bool-string.js b/js/src/tests/non262/Intl/NumberFormat/use-grouping-bool-string.js
new file mode 100644
index 0000000000..4216c874f0
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/use-grouping-bool-string.js
@@ -0,0 +1,10 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+let nf1 = new Intl.NumberFormat("en", {useGrouping: "true"});
+assertEq(nf1.format(1000), "1,000");
+
+let nf2 = new Intl.NumberFormat("en", {useGrouping: "false"});
+assertEq(nf2.format(1000), "1,000");
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
diff --git a/js/src/tests/non262/Intl/NumberFormat/use-grouping.js b/js/src/tests/non262/Intl/NumberFormat/use-grouping.js
new file mode 100644
index 0000000000..8fcb2fb51e
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/use-grouping.js
@@ -0,0 +1,97 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl")||release_or_beta)
+
+const tests = {
+  // minimumGroupingDigits is one for "en" (English).
+  "en": {
+    values: [
+      {
+        value: 1000,
+        useGroupings: {
+          auto: "1,000",
+          always: "1,000",
+          min2: "1000",
+          "": "1000",
+        },
+      },
+      {
+        value: 10000,
+        useGroupings: {
+          auto: "10,000",
+          always: "10,000",
+          min2: "10,000",
+          "": "10000",
+        },
+      },
+    ],
+  },
+
+  // minimumGroupingDigits is two for "pl" (Polish).
+  "pl": {
+    values: [
+      {
+        value: 1000,
+        useGroupings: {
+          auto: "1000",
+          always: "1 000",
+          min2: "1000",
+          "": "1000",
+        },
+      },
+      {
+        value: 10000,
+        useGroupings: {
+          auto: "10 000",
+          always: "10 000",
+          min2: "10 000",
+          "": "10000",
+        },
+      },
+    ],
+  },
+};
+
+for (let [locale, {options = {}, values}] of Object.entries(tests)) {
+  for (let {value, useGroupings} of values) {
+    for (let [useGrouping, expected] of Object.entries(useGroupings)) {
+      let nf = new Intl.NumberFormat(locale, {...options, useGrouping});
+      assertEq(nf.format(value), expected, `locale=${locale}, value=${value}, useGrouping=${useGrouping}`);
+    }
+  }
+}
+
+// Resolved options.
+for (let [useGrouping, expected] of [
+  [false, false],
+  ["", false],
+  [0, false],
+  [null, false],
+
+  ["auto", "auto"],
+  [undefined, "auto"],
+
+  ["always", "always"],
+  [true, "always"],
+
+  ["min2", "min2"],
+
+  // Unsupported values fallback to "auto"
+  ["true", "auto"],
+  ["false", "auto"],
+  ["none", "auto"],
+  ["yes", "auto"],
+  ["no", "auto"],
+  [{}, "auto"],
+  [123, "auto"],
+  [123n, "auto"],
+]) {
+  let nf = new Intl.NumberFormat("en", {useGrouping});
+  assertEq(nf.resolvedOptions().useGrouping , expected);
+}
+
+// Throws a TypeError if ToString fails.
+for (let useGrouping of [Object.create(null), Symbol()]) {
+  assertThrowsInstanceOf(() => new Intl.NumberFormat("en", {useGrouping}), TypeError);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
-- 
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