1 files changed, 36 insertions, 0 deletions
diff --git a/js/src/builtin/BigInt.js b/js/src/builtin/BigInt.js
new file mode 100644
index 0000000000..c7aa3859a8
--- /dev/null
+++ b/js/src/builtin/BigInt.js
@@ -0,0 +1,36 @@
+/* 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/. */
+
+#if JS_HAS_INTL_API
+/**
+ * Format this BigInt object into a string, using the locale and formatting
+ * options provided.
+ *
+ * Spec PR: https://github.com/tc39/ecma402/pull/236
+ */
+function BigInt_toLocaleString() {
+  // Step 1. Note that valueOf enforces "thisBigIntValue" restrictions.
+  var x = callFunction(std_BigInt_valueOf, this);
+
+  var locales = ArgumentsLength() ? GetArgument(0) : undefined;
+  var options = ArgumentsLength() > 1 ? GetArgument(1) : undefined;
+
+  // Step 2.
+  var numberFormat;
+  if (locales === undefined && options === undefined) {
+    // This cache only optimizes when no explicit locales and options
+    // arguments were supplied.
+    if (!intl_IsRuntimeDefaultLocale(numberFormatCache.runtimeDefaultLocale)) {
+      numberFormatCache.numberFormat = intl_NumberFormat(locales, options);
+      numberFormatCache.runtimeDefaultLocale = intl_RuntimeDefaultLocale();
+    }
+    numberFormat = numberFormatCache.numberFormat;
+  } else {
+    numberFormat = intl_NumberFormat(locales, options);
+  }
+
+  // Step 3.
+  return intl_FormatNumber(numberFormat, x, /* formatToParts = */ false);
+}
+#endif  // JS_HAS_INTL_API