1 files changed, 37 insertions, 0 deletions
diff --git a/js/src/builtin/Error.js b/js/src/builtin/Error.js
new file mode 100644
index 0000000000..a8633a0a53
--- /dev/null
+++ b/js/src/builtin/Error.js
@@ -0,0 +1,37 @@
+/* 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/. */
+
+/* ES6 20140718 draft 19.5.3.4. */
+function ErrorToString() {
+  /* Steps 1-2. */
+  var obj = this;
+  if (!IsObject(obj)) {
+    ThrowTypeError(JSMSG_INCOMPATIBLE_PROTO, "Error", "toString", "value");
+  }
+
+  /* Steps 3-5. */
+  var name = obj.name;
+  name = name === undefined ? "Error" : ToString(name);
+
+  /* Steps 6-8. */
+  var msg = obj.message;
+  msg = msg === undefined ? "" : ToString(msg);
+
+  /* Step 9. */
+  if (name === "") {
+    return msg;
+  }
+
+  /* Step 10. */
+  if (msg === "") {
+    return name;
+  }
+
+  /* Step 11. */
+  return name + ": " + msg;
+}
+
+function ErrorToStringWithTrailingNewline() {
+  return FUN_APPLY(ErrorToString, this, []) + "\n";
+}