Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1173 insertions, 0 deletions

diff --git a/js/src/builtin/Array.js b/js/src/builtin/Array.js
new file mode 100644
index 0000000000..4f1f48d3bc
--- /dev/null
+++ b/js/src/builtin/Array.js
@@ -0,0 +1,1173 @@
+/* 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/. */
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.14 Array.prototype.indexOf ( searchElement [ , fromIndex ] )
+function ArrayIndexOf(searchElement/*, fromIndex*/) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var len = ToLength(O.length);
+
+    // Step 3.
+    if (len === 0)
+        return -1;
+
+    // Steps 4-5.
+    var n = arguments.length > 1 ? ToInteger(arguments[1]) : 0;
+
+    // Step 6.
+    if (n >= len)
+        return -1;
+
+    // Steps 7-8.
+    var k;
+    if (n >= 0) {
+        // Step 7.a.
+        k = n;
+    } else {
+        // Step 8.a.
+        k = len + n;
+
+        // Step 8.b.
+        if (k < 0)
+            k = 0;
+    }
+
+    // Step 9.
+    for (; k < len; k++) {
+        if (k in O && O[k] === searchElement)
+            return k;
+    }
+
+    // Step 10.
+    return -1;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.17 Array.prototype.lastIndexOf ( searchElement [ , fromIndex ] )
+function ArrayLastIndexOf(searchElement/*, fromIndex*/) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var len = ToLength(O.length);
+
+    // Step 3.
+    if (len === 0)
+        return -1;
+
+    // Step 4.
+    var n = arguments.length > 1 ? ToInteger(arguments[1]) : len - 1;
+
+    // Steps 5-6.
+    var k;
+    if (n > len - 1)
+        k = len - 1;
+    else if (n < 0)
+        k = len + n;
+    else
+        k = n;
+
+    // Step 7.
+    for (; k >= 0; k--) {
+        if (k in O && O[k] === searchElement)
+            return k;
+    }
+
+    // Step 8.
+    return -1;
+}
+
+/* ES5 15.4.4.16. */
+function ArrayEvery(callbackfn/*, thisArg*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Steps 2-3. */
+    var len = ToLength(O.length);
+
+    /* Step 4. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.every");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 5. */
+    var T = arguments.length > 1 ? arguments[1] : void 0;
+
+    /* Steps 6-7. */
+    /* Steps a (implicit), and d. */
+    for (var k = 0; k < len; k++) {
+        /* Step b */
+        if (k in O) {
+            /* Step c. */
+            if (!callContentFunction(callbackfn, T, O[k], k, O))
+                return false;
+        }
+    }
+
+    /* Step 8. */
+    return true;
+}
+
+/* ES5 15.4.4.17. */
+function ArraySome(callbackfn/*, thisArg*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Steps 2-3. */
+    var len = ToLength(O.length);
+
+    /* Step 4. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.some");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 5. */
+    var T = arguments.length > 1 ? arguments[1] : void 0;
+
+    /* Steps 6-7. */
+    /* Steps a (implicit), and d. */
+    for (var k = 0; k < len; k++) {
+        /* Step b */
+        if (k in O) {
+            /* Step c. */
+            if (callContentFunction(callbackfn, T, O[k], k, O))
+                return true;
+        }
+    }
+
+    /* Step 8. */
+    return false;
+}
+
+// ES2018 draft rev 3bbc87cd1b9d3bf64c3e68ca2fe9c5a3f2c304c0
+// 22.1.3.25 Array.prototype.sort ( comparefn )
+function ArraySort(comparefn) {
+    // Step 1.
+    if (comparefn !== undefined) {
+        if (!IsCallable(comparefn))
+            ThrowTypeError(JSMSG_BAD_SORT_ARG);
+    }
+
+    // Step 2.
+    var O = ToObject(this);
+
+    // First try to sort the array in native code, if that fails, indicated by
+    // returning |false| from ArrayNativeSort, sort it in self-hosted code.
+    if (callFunction(ArrayNativeSort, O, comparefn))
+        return O;
+
+    // Step 3.
+    var len = ToLength(O.length);
+
+    if (len <= 1)
+      return O;
+
+    /* 22.1.3.25.1 Runtime Semantics: SortCompare( x, y ) */
+    var wrappedCompareFn = comparefn;
+    comparefn = function(x, y) {
+        /* Steps 1-3. */
+        if (x === undefined) {
+            if (y === undefined)
+                return 0;
+           return 1;
+        }
+        if (y === undefined)
+            return -1;
+
+        /* Step 4.a. */
+        var v = ToNumber(wrappedCompareFn(x, y));
+
+        /* Step 4.b-c. */
+        return v !== v ? 0 : v;
+    };
+
+    return MergeSort(O, len, comparefn);
+}
+
+/* ES5 15.4.4.18. */
+function ArrayForEach(callbackfn/*, thisArg*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Steps 2-3. */
+    var len = ToLength(O.length);
+
+    /* Step 4. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.forEach");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 5. */
+    var T = arguments.length > 1 ? arguments[1] : void 0;
+
+    /* Steps 6-7. */
+    /* Steps a (implicit), and d. */
+    for (var k = 0; k < len; k++) {
+        /* Step b */
+        if (k in O) {
+            /* Step c. */
+            callContentFunction(callbackfn, T, O[k], k, O);
+        }
+    }
+
+    /* Step 8. */
+    return void 0;
+}
+
+/* ES 2016 draft Mar 25, 2016 22.1.3.15. */
+function ArrayMap(callbackfn/*, thisArg*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Step 2. */
+    var len = ToLength(O.length);
+
+    /* Step 3. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.map");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 4. */
+    var T = arguments.length > 1 ? arguments[1] : void 0;
+
+    /* Steps 5. */
+    var A = ArraySpeciesCreate(O, len);
+
+    /* Steps 6-7. */
+    /* Steps 7.a (implicit), and 7.d. */
+    for (var k = 0; k < len; k++) {
+        /* Steps 7.b-c. */
+        if (k in O) {
+            /* Steps 7.c.i-iii. */
+            var mappedValue = callContentFunction(callbackfn, T, O[k], k, O);
+            _DefineDataProperty(A, k, mappedValue);
+        }
+    }
+
+    /* Step 8. */
+    return A;
+}
+
+/* ES 2016 draft Mar 25, 2016 22.1.3.7 Array.prototype.filter. */
+function ArrayFilter(callbackfn/*, thisArg*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Step 2. */
+    var len = ToLength(O.length);
+
+    /* Step 3. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.filter");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 4. */
+    var T = arguments.length > 1 ? arguments[1] : void 0;
+
+    /* Step 5. */
+    var A = ArraySpeciesCreate(O, 0);
+
+    /* Steps 6-8. */
+    /* Steps 8.a (implicit), and 8.d. */
+    for (var k = 0, to = 0; k < len; k++) {
+        /* Steps 8.b-c. */
+        if (k in O) {
+            /* Step 8.c.i. */
+            var kValue = O[k];
+            /* Step 8.c.ii. */
+            var selected = callContentFunction(callbackfn, T, kValue, k, O);
+            /* Step 8.c.iii. */
+            if (selected)
+                _DefineDataProperty(A, to++, kValue);
+        }
+    }
+
+    /* Step 9. */
+    return A;
+}
+
+/* ES5 15.4.4.21. */
+function ArrayReduce(callbackfn/*, initialValue*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Steps 2-3. */
+    var len = ToLength(O.length);
+
+    /* Step 4. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.reduce");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 6. */
+    var k = 0;
+
+    /* Steps 5, 7-8. */
+    var accumulator;
+    if (arguments.length > 1) {
+        accumulator = arguments[1];
+    } else {
+        /* Step 5. */
+        // Add an explicit |throw| here and below to inform Ion that the
+        // ThrowTypeError calls exit this function.
+        if (len === 0)
+            throw ThrowTypeError(JSMSG_EMPTY_ARRAY_REDUCE);
+
+        // Use a |do-while| loop to let Ion know that the loop will definitely
+        // be entered at least once. When Ion is then also able to inline the
+        // |in| operator, it can optimize away the whole loop.
+        var kPresent = false;
+        do {
+            if (k in O) {
+                kPresent = true;
+                break;
+            }
+        } while (++k < len);
+        if (!kPresent)
+          throw ThrowTypeError(JSMSG_EMPTY_ARRAY_REDUCE);
+
+        // Moved outside of the loop to ensure the assignment is non-conditional.
+        accumulator = O[k++];
+    }
+
+    /* Step 9. */
+    /* Steps a (implicit), and d. */
+    for (; k < len; k++) {
+        /* Step b */
+        if (k in O) {
+            /* Step c. */
+            accumulator = callbackfn(accumulator, O[k], k, O);
+        }
+    }
+
+    /* Step 10. */
+    return accumulator;
+}
+
+/* ES5 15.4.4.22. */
+function ArrayReduceRight(callbackfn/*, initialValue*/) {
+    /* Step 1. */
+    var O = ToObject(this);
+
+    /* Steps 2-3. */
+    var len = ToLength(O.length);
+
+    /* Step 4. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.reduce");
+    if (!IsCallable(callbackfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, callbackfn));
+
+    /* Step 6. */
+    var k = len - 1;
+
+    /* Steps 5, 7-8. */
+    var accumulator;
+    if (arguments.length > 1) {
+        accumulator = arguments[1];
+    } else {
+        /* Step 5. */
+        // Add an explicit |throw| here and below to inform Ion that the
+        // ThrowTypeError calls exit this function.
+        if (len === 0)
+            throw ThrowTypeError(JSMSG_EMPTY_ARRAY_REDUCE);
+
+        // Use a |do-while| loop to let Ion know that the loop will definitely
+        // be entered at least once. When Ion is then also able to inline the
+        // |in| operator, it can optimize away the whole loop.
+        var kPresent = false;
+        do {
+            if (k in O) {
+                kPresent = true;
+                break;
+            }
+        } while (--k >= 0);
+        if (!kPresent)
+            throw ThrowTypeError(JSMSG_EMPTY_ARRAY_REDUCE);
+
+        // Moved outside of the loop to ensure the assignment is non-conditional.
+        accumulator = O[k--];
+    }
+
+    /* Step 9. */
+    /* Steps a (implicit), and d. */
+    for (; k >= 0; k--) {
+        /* Step b */
+        if (k in O) {
+            /* Step c. */
+            accumulator = callbackfn(accumulator, O[k], k, O);
+        }
+    }
+
+    /* Step 10. */
+    return accumulator;
+}
+
+/* ES6 draft 2013-05-14 15.4.3.23. */
+function ArrayFind(predicate/*, thisArg*/) {
+    /* Steps 1-2. */
+    var O = ToObject(this);
+
+    /* Steps 3-5. */
+    var len = ToLength(O.length);
+
+    /* Step 6. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.find");
+    if (!IsCallable(predicate))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, predicate));
+
+    /* Step 7. */
+    var T = arguments.length > 1 ? arguments[1] : undefined;
+
+    /* Steps 8-9. */
+    /* Steps a (implicit), and g. */
+    for (var k = 0; k < len; k++) {
+        /* Steps a-c. */
+        var kValue = O[k];
+        /* Steps d-f. */
+        if (callContentFunction(predicate, T, kValue, k, O))
+            return kValue;
+    }
+
+    /* Step 10. */
+    return undefined;
+}
+
+/* ES6 draft 2013-05-14 15.4.3.23. */
+function ArrayFindIndex(predicate/*, thisArg*/) {
+    /* Steps 1-2. */
+    var O = ToObject(this);
+
+    /* Steps 3-5. */
+    var len = ToLength(O.length);
+
+    /* Step 6. */
+    if (arguments.length === 0)
+        ThrowTypeError(JSMSG_MISSING_FUN_ARG, 0, "Array.prototype.find");
+    if (!IsCallable(predicate))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, predicate));
+
+    /* Step 7. */
+    var T = arguments.length > 1 ? arguments[1] : undefined;
+
+    /* Steps 8-9. */
+    /* Steps a (implicit), and g. */
+    for (var k = 0; k < len; k++) {
+        /* Steps a-f. */
+        if (callContentFunction(predicate, T, O[k], k, O))
+            return k;
+    }
+
+    /* Step 10. */
+    return -1;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.3 Array.prototype.copyWithin ( target, start [ , end ] )
+function ArrayCopyWithin(target, start, end = undefined) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var len = ToLength(O.length);
+
+    // Step 3.
+    var relativeTarget = ToInteger(target);
+
+    // Step 4.
+    var to = relativeTarget < 0 ? std_Math_max(len + relativeTarget, 0)
+                                : std_Math_min(relativeTarget, len);
+
+    // Step 5.
+    var relativeStart = ToInteger(start);
+
+    // Step 6.
+    var from = relativeStart < 0 ? std_Math_max(len + relativeStart, 0)
+                                 : std_Math_min(relativeStart, len);
+
+    // Step 7.
+    var relativeEnd = end === undefined ? len : ToInteger(end);
+
+    // Step 8.
+    var final = relativeEnd < 0 ? std_Math_max(len + relativeEnd, 0)
+                                : std_Math_min(relativeEnd, len);
+
+    // Step 9.
+    var count = std_Math_min(final - from, len - to);
+
+    // Steps 10-12.
+    if (from < to && to < (from + count)) {
+        // Steps 10.b-c.
+        from = from + count - 1;
+        to = to + count - 1;
+
+        // Step 12.
+        while (count > 0) {
+            if (from in O)
+                O[to] = O[from];
+            else
+                delete O[to];
+
+            from--;
+            to--;
+            count--;
+        }
+    } else {
+        // Step 12.
+        while (count > 0) {
+            if (from in O)
+                O[to] = O[from];
+            else
+                delete O[to];
+
+            from++;
+            to++;
+            count--;
+        }
+    }
+
+    // Step 13.
+    return O;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.6 Array.prototype.fill ( value [ , start [ , end ] ] )
+function ArrayFill(value, start = 0, end = undefined) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var len = ToLength(O.length);
+
+    // Step 3.
+    var relativeStart = ToInteger(start);
+
+    // Step 4.
+    var k = relativeStart < 0
+            ? std_Math_max(len + relativeStart, 0)
+            : std_Math_min(relativeStart, len);
+
+    // Step 5.
+    var relativeEnd = end === undefined ? len : ToInteger(end);
+
+    // Step 6.
+    var final = relativeEnd < 0
+                ? std_Math_max(len + relativeEnd, 0)
+                : std_Math_min(relativeEnd, len);
+
+    // Step 7.
+    for (; k < final; k++) {
+        O[k] = value;
+    }
+
+    // Step 8.
+    return O;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.13 Array.prototype.includes ( searchElement [ , fromIndex ] )
+function ArrayIncludes(searchElement, fromIndex = 0) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var len = ToLength(O.length);
+
+    // Step 3.
+    if (len === 0)
+        return false;
+
+    // Steps 4-5.
+    var n = ToInteger(fromIndex);
+
+    // Steps 6-7.
+    var k;
+    if (n >= 0) {
+        // Step 6.a.
+        k = n;
+    } else {
+        // Step 7.a.
+        k = len + n;
+
+        // Step 7.b.
+        if (k < 0)
+            k = 0;
+    }
+
+    // Step 8.
+    while (k < len) {
+        // Steps 8.a-c.
+        if (SameValueZero(searchElement, O[k]))
+            return true;
+
+        // Step 8.d.
+        k++;
+    }
+
+    // Step 9.
+    return false;
+}
+
+// ES6 draft specification, section 22.1.5.1, version 2013-09-05.
+function CreateArrayIterator(obj, kind) {
+    var iteratedObject = ToObject(obj);
+    var iterator = NewArrayIterator();
+    UnsafeSetReservedSlot(iterator, ITERATOR_SLOT_TARGET, iteratedObject);
+    UnsafeSetReservedSlot(iterator, ITERATOR_SLOT_NEXT_INDEX, 0);
+    UnsafeSetReservedSlot(iterator, ITERATOR_SLOT_ITEM_KIND, kind);
+    return iterator;
+}
+
+// ES6, 22.1.5.2.1
+// http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%arrayiteratorprototype%.next
+function ArrayIteratorNext() {
+    // Step 1-3.
+    var obj;
+    if (!IsObject(this) || (obj = GuardToArrayIterator(this)) === null) {
+        return callFunction(CallArrayIteratorMethodIfWrapped, this,
+                            "ArrayIteratorNext");
+    }
+
+    // Step 4.
+    var a = UnsafeGetReservedSlot(obj, ITERATOR_SLOT_TARGET);
+    var result = { value: undefined, done: false };
+
+    // Step 5.
+    if (a === null) {
+      result.done = true;
+      return result;
+    }
+
+    // Step 6.
+    // The index might not be an integer, so we have to do a generic get here.
+    var index = UnsafeGetReservedSlot(obj, ITERATOR_SLOT_NEXT_INDEX);
+
+    // Step 7.
+    var itemKind = UnsafeGetInt32FromReservedSlot(obj, ITERATOR_SLOT_ITEM_KIND);
+
+    // Step 8-9.
+    var len;
+    if (IsPossiblyWrappedTypedArray(a)) {
+        len = PossiblyWrappedTypedArrayLength(a);
+
+        // If the length is non-zero, the buffer can't be detached.
+        if (len === 0) {
+            if (PossiblyWrappedTypedArrayHasDetachedBuffer(a))
+                ThrowTypeError(JSMSG_TYPED_ARRAY_DETACHED);
+        }
+    } else {
+        len = ToLength(a.length);
+    }
+
+    // Step 10.
+    if (index >= len) {
+        UnsafeSetReservedSlot(obj, ITERATOR_SLOT_TARGET, null);
+        result.done = true;
+        return result;
+    }
+
+    // Step 11.
+    UnsafeSetReservedSlot(obj, ITERATOR_SLOT_NEXT_INDEX, index + 1);
+
+    // Step 16.
+    if (itemKind === ITEM_KIND_VALUE) {
+        result.value = a[index];
+        return result;
+    }
+
+    // Step 13.
+    if (itemKind === ITEM_KIND_KEY_AND_VALUE) {
+        var pair = [index, a[index]];
+        result.value = pair;
+        return result;
+    }
+
+    // Step 12.
+    assert(itemKind === ITEM_KIND_KEY, itemKind);
+    result.value = index;
+    return result;
+}
+
+// Uncloned functions with `$` prefix are allocated as extended function
+// to store the original name in `_SetCanonicalName`.
+function $ArrayValues() {
+    return CreateArrayIterator(this, ITEM_KIND_VALUE);
+}
+_SetCanonicalName($ArrayValues, "values");
+
+function ArrayEntries() {
+    return CreateArrayIterator(this, ITEM_KIND_KEY_AND_VALUE);
+}
+
+function ArrayKeys() {
+    return CreateArrayIterator(this, ITEM_KIND_KEY);
+}
+
+// ES 2017 draft 0f10dba4ad18de92d47d421f378233a2eae8f077 22.1.2.1
+function ArrayFrom(items, mapfn = undefined, thisArg = undefined) {
+    // Step 1.
+    var C = this;
+
+    // Steps 2-3.
+    var mapping = mapfn !== undefined;
+    if (mapping && !IsCallable(mapfn))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(1, mapfn));
+    var T = thisArg;
+
+    // Step 4.
+    // Inlined: GetMethod, steps 1-2.
+    var usingIterator = items[std_iterator];
+
+    // Step 5.
+    // Inlined: GetMethod, step 3.
+    if (usingIterator !== undefined && usingIterator !== null) {
+        // Inlined: GetMethod, step 4.
+        if (!IsCallable(usingIterator))
+            ThrowTypeError(JSMSG_NOT_ITERABLE, DecompileArg(0, items));
+
+        // Steps 5.a-b.
+        var A = IsConstructor(C) ? new C() : [];
+
+        // Step 5.c.
+        var iterator = MakeIteratorWrapper(items, usingIterator);
+
+        // Step 5.d.
+        var k = 0;
+
+        // Step 5.e
+        for (var nextValue of allowContentIter(iterator)) {
+            // Step 5.e.i.
+            // Disabled for performance reason.  We won't hit this case on
+            // normal array, since _DefineDataProperty will throw before it.
+            // We could hit this when |A| is a proxy and it ignores
+            // |_DefineDataProperty|, but it happens only after too long loop.
+            /*
+            if (k >= 0x1fffffffffffff)
+                ThrowTypeError(JSMSG_TOO_LONG_ARRAY);
+            */
+
+            // Steps 5.e.vi-vii.
+            var mappedValue = mapping ? callContentFunction(mapfn, T, nextValue, k) : nextValue;
+
+            // Steps 5.e.ii (reordered), 5.e.viii.
+            _DefineDataProperty(A, k++, mappedValue);
+        }
+
+        // Step 5.e.iv.
+        A.length = k;
+        return A;
+    }
+
+    // Step 7 is an assertion: items is not an Iterator. Testing this is
+    // literally the very last thing we did, so we don't assert here.
+
+    // Steps 8-9.
+    var arrayLike = ToObject(items);
+
+    // Steps 10-11.
+    var len = ToLength(arrayLike.length);
+
+    // Steps 12-14.
+    var A = IsConstructor(C) ? new C(len) : std_Array(len);
+
+    // Steps 15-16.
+    for (var k = 0; k < len; k++) {
+        // Steps 16.a-c.
+        var kValue = items[k];
+
+        // Steps 16.d-e.
+        var mappedValue = mapping ? callContentFunction(mapfn, T, kValue, k) : kValue;
+
+        // Steps 16.f-g.
+        _DefineDataProperty(A, k, mappedValue);
+    }
+
+    // Steps 17-18.
+    A.length = len;
+
+    // Step 19.
+    return A;
+}
+
+function MakeIteratorWrapper(items, method) {
+    assert(IsCallable(method), "method argument is a function");
+
+    // This function is not inlined in ArrayFrom, because function default
+    // parameters combined with nested functions are currently not optimized
+    // correctly.
+    return {
+        // Use a named function expression instead of a method definition, so
+        // we don't create an inferred name for this function at runtime.
+        [std_iterator]: function IteratorMethod() {
+            return callContentFunction(method, items);
+        },
+    };
+}
+
+// ES2015 22.1.3.27 Array.prototype.toString.
+function ArrayToString() {
+    // Steps 1-2.
+    var array = ToObject(this);
+
+    // Steps 3-4.
+    var func = array.join;
+
+    // Steps 5-6.
+    if (!IsCallable(func))
+        return callFunction(std_Object_toString, array);
+    return callContentFunction(func, array);
+}
+
+// ES2017 draft rev f8a9be8ea4bd97237d176907a1e3080dce20c68f
+// 22.1.3.27 Array.prototype.toLocaleString ([ reserved1 [ , reserved2 ] ])
+// ES2017 Intl draft rev 78bbe7d1095f5ff3760ac4017ed366026e4cb276
+// 13.4.1 Array.prototype.toLocaleString ([ locales [ , options ]])
+function ArrayToLocaleString(locales, options) {
+    // Step 1 (ToObject already performed in native code).
+    assert(IsObject(this), "|this| should be an object");
+    var array = this;
+
+    // Step 2.
+    var len = ToLength(array.length);
+
+    // Step 4.
+    if (len === 0)
+        return "";
+
+    // Step 5.
+    var firstElement = array[0];
+
+    // Steps 6-7.
+    var R;
+    if (firstElement === undefined || firstElement === null) {
+        R = "";
+    } else {
+#if JS_HAS_INTL_API
+        R = ToString(callContentFunction(firstElement.toLocaleString, firstElement, locales, options));
+#else
+        R = ToString(callContentFunction(firstElement.toLocaleString, firstElement));
+#endif
+    }
+
+    // Step 3 (reordered).
+    // We don't (yet?) implement locale-dependent separators.
+    var separator = ",";
+
+    // Steps 8-9.
+    for (var k = 1; k < len; k++) {
+        // Step 9.b.
+        var nextElement = array[k];
+
+        // Steps 9.a, 9.c-e.
+        R += separator;
+        if (!(nextElement === undefined || nextElement === null)) {
+#if JS_HAS_INTL_API
+            R += ToString(callContentFunction(nextElement.toLocaleString, nextElement, locales, options));
+#else
+            R += ToString(callContentFunction(nextElement.toLocaleString, nextElement));
+#endif
+        }
+    }
+
+    // Step 10.
+    return R;
+}
+
+// ES 2016 draft Mar 25, 2016 22.1.2.5.
+function $ArraySpecies() {
+    // Step 1.
+    return this;
+}
+_SetCanonicalName($ArraySpecies, "get [Symbol.species]");
+
+// ES 2016 draft Mar 25, 2016 9.4.2.3.
+function ArraySpeciesCreate(originalArray, length) {
+    // Step 1.
+    assert(typeof length == "number", "length should be a number");
+    assert(length >= 0, "length should be a non-negative number");
+
+    // Step 2.
+    // eslint-disable-next-line no-compare-neg-zero
+    if (length === -0)
+        length = 0;
+
+    // Step 4, 6.
+    if (!IsArray(originalArray))
+        return std_Array(length);
+
+    // Step 5.a.
+    var C = originalArray.constructor;
+
+    // Step 5.b.
+    if (IsConstructor(C) && IsCrossRealmArrayConstructor(C))
+        return std_Array(length);
+
+    // Step 5.c.
+    if (IsObject(C)) {
+        // Step 5.c.i.
+        C = C[std_species];
+
+        // Optimized path for an ordinary Array.
+        if (C === GetBuiltinConstructor("Array"))
+            return std_Array(length);
+
+        // Step 5.c.ii.
+        if (C === null)
+            return std_Array(length);
+    }
+
+    // Step 6.
+    if (C === undefined)
+        return std_Array(length);
+
+    // Step 7.
+    if (!IsConstructor(C))
+        ThrowTypeError(JSMSG_NOT_CONSTRUCTOR, "constructor property");
+
+    // Step 8.
+    return new C(length);
+}
+
+// ES 2017 draft (April 8, 2016) 22.1.3.1.1
+function IsConcatSpreadable(O) {
+    // Step 1.
+    if (!IsObject(O))
+        return false;
+
+    // Step 2.
+    var spreadable = O[std_isConcatSpreadable];
+
+    // Step 3.
+    if (spreadable !== undefined)
+        return ToBoolean(spreadable);
+
+    // Step 4.
+    return IsArray(O);
+}
+
+// ES 2016 draft Mar 25, 2016 22.1.3.1.
+// Note: Array.prototype.concat.length is 1.
+function ArrayConcat(arg1) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var A = ArraySpeciesCreate(O, 0);
+
+    // Step 3.
+    var n = 0;
+
+    // Step 4 (implicit in |arguments|).
+
+    // Step 5.
+    var i = 0, argsLen = arguments.length;
+
+    // Step 5.a (first element).
+    var E = O;
+
+    var k, len;
+    while (true) {
+        // Steps 5.b-c.
+        if (IsConcatSpreadable(E)) {
+            // Step 5.c.ii.
+            len = ToLength(E.length);
+
+            // Step 5.c.iii.
+            if (n + len > MAX_NUMERIC_INDEX)
+                ThrowTypeError(JSMSG_TOO_LONG_ARRAY);
+
+            if (IsPackedArray(A) && IsPackedArray(E)) {
+                // Step 5.c.i, 5.c.iv, and 5.c.iv.5.
+                for (k = 0; k < len; k++) {
+                    // Steps 5.c.iv.1-3.
+                    // IsPackedArray(E) ensures that |k in E| is always true.
+                    _DefineDataProperty(A, n, E[k]);
+
+                    // Step 5.c.iv.4.
+                    n++;
+                }
+            } else {
+                // Step 5.c.i, 5.c.iv, and 5.c.iv.5.
+                for (k = 0; k < len; k++) {
+                    // Steps 5.c.iv.1-3.
+                    if (k in E)
+                        _DefineDataProperty(A, n, E[k]);
+
+                    // Step 5.c.iv.4.
+                    n++;
+                }
+            }
+        } else {
+            // Step 5.d.i.
+            if (n >= MAX_NUMERIC_INDEX)
+                ThrowTypeError(JSMSG_TOO_LONG_ARRAY);
+
+            // Step 5.d.ii.
+            _DefineDataProperty(A, n, E);
+
+            // Step 5.d.iii.
+            n++;
+        }
+
+        if (i >= argsLen)
+            break;
+        // Step 5.a (subsequent elements).
+        E = arguments[i];
+        i++;
+    }
+
+    // Step 6.
+    A.length = n;
+
+    // Step 7.
+    return A;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.11 Array.prototype.flatMap ( mapperFunction [ , thisArg ] )
+function ArrayFlatMap(mapperFunction/*, thisArg*/) {
+    // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var sourceLen = ToLength(O.length);
+
+    // Step 3.
+    if (!IsCallable(mapperFunction))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapperFunction));
+
+    // Step 4.
+    var T = arguments.length > 1 ? arguments[1] : undefined;
+
+    // Step 5.
+    var A = ArraySpeciesCreate(O, 0);
+
+    // Step 6.
+    FlattenIntoArray(A, O, sourceLen, 0, 1, mapperFunction, T);
+
+    // Step 7.
+    return A;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.10 Array.prototype.flat ( [ depth ] )
+function ArrayFlat(/* depth */) {
+     // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var sourceLen = ToLength(O.length);
+
+    // Step 3.
+    var depthNum = 1;
+
+    // Step 4.
+    if (arguments.length > 0 && arguments[0] !== undefined)
+        depthNum = ToInteger(arguments[0]);
+
+    // Step 5.
+    var A = ArraySpeciesCreate(O, 0);
+
+    // Step 6.
+    FlattenIntoArray(A, O, sourceLen, 0, depthNum);
+
+    // Step 7.
+    return A;
+}
+
+// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// 22.1.3.10.1 FlattenIntoArray ( target, source, sourceLen, start, depth [ , mapperFunction, thisArg ] )
+function FlattenIntoArray(target, source, sourceLen, start, depth, mapperFunction, thisArg) {
+    // Step 1.
+    var targetIndex = start;
+
+    // Steps 2-3.
+    for (var sourceIndex = 0; sourceIndex < sourceLen; sourceIndex++) {
+        // Steps 3.a-c.
+        if (sourceIndex in source) {
+            // Step 3.c.i.
+            var element = source[sourceIndex];
+
+            if (mapperFunction) {
+                // Step 3.c.ii.1.
+                assert(arguments.length === 7, "thisArg is present");
+
+                // Step 3.c.ii.2.
+                element = callContentFunction(mapperFunction, thisArg, element, sourceIndex, source);
+            }
+
+            // Step 3.c.iii.
+            var shouldFlatten = false;
+
+            // Step 3.c.iv.
+            if (depth > 0) {
+                // Step 3.c.iv.1.
+                shouldFlatten = IsArray(element);
+            }
+
+            // Step 3.c.v.
+            if (shouldFlatten) {
+                // Step 3.c.v.1.
+                var elementLen = ToLength(element.length);
+
+                // Step 3.c.v.2.
+                targetIndex = FlattenIntoArray(target, element, elementLen, targetIndex, depth - 1);
+            } else {
+                // Step 3.c.vi.1.
+                if (targetIndex >= MAX_NUMERIC_INDEX)
+                    ThrowTypeError(JSMSG_TOO_LONG_ARRAY);
+
+                // Step 3.c.vi.2.
+                _DefineDataProperty(target, targetIndex, element);
+
+                // Step 3.c.vi.3.
+                targetIndex++;
+            }
+        }
+    }
+
+    // Step 4.
+    return targetIndex;
+}
+
+// https://github.com/tc39/proposal-relative-indexing-method
+// Array.prototype.at ( index )
+function ArrayAt(index) {
+     // Step 1.
+    var O = ToObject(this);
+
+    // Step 2.
+    var len = ToLength(O.length);
+
+    // Step 3.
+    var relativeIndex = ToInteger(index);
+
+    // Steps 4-5.
+    var k;
+    if (relativeIndex >= 0) {
+        k = relativeIndex;
+    } else {
+        k = len + relativeIndex;
+    }
+
+    // Step 6.
+    if (k < 0 || k >= len) {
+        return undefined;
+    }
+
+    // Step 7.
+    return O[k];
+}
+// This function is only barely too long for normal inlining.
+_SetIsInlinableLargeFunction(ArrayAt);