1 files changed, 34 insertions, 0 deletions
diff --git a/js/src/builtin/BigInt.js b/js/src/builtin/BigInt.js
new file mode 100644
index 0000000000..3ed3da5933
--- /dev/null
+++ b/js/src/builtin/BigInt.js
@@ -0,0 +1,34 @@
+/* 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/. */
+
+/**
+ * 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 = arguments.length > 0 ? arguments[0] : undefined;
+    var options = arguments.length > 1 ? arguments[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 (!IsRuntimeDefaultLocale(numberFormatCache.runtimeDefaultLocale)) {
+            numberFormatCache.numberFormat = intl_NumberFormat(locales, options);
+            numberFormatCache.runtimeDefaultLocale = RuntimeDefaultLocale();
+        }
+        numberFormat = numberFormatCache.numberFormat;
+    } else {
+        numberFormat = intl_NumberFormat(locales, options);
+    }
+
+    // Step 3.
+    return intl_FormatNumber(numberFormat, x, /* formatToParts = */ false);
+}