v8/test/mjsunit/es6/string-iterator4.js
Hai Dang 6cb0a014de Add string iterator protector.
The protector is useful for follow-up optimizations on string iterator.
Tests are also added.

Change-Id: I416037c742628c4d4d3b878d0df727a9ae7162f7
Reviewed-on: https://chromium-review.googlesource.com/1251122
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Hai Dang <dhai@google.com>
Cr-Commit-Position: refs/heads/master@{#56315}
2018-10-01 13:15:53 +00:00

31 lines
936 B
JavaScript

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax --no-stress-opt
// Tests for wrapped strings.
var str = new String('ott');
assertTrue(%StringIteratorProtector());
assertEquals(['o', 't', 't'], [...str]);
function iterator_fn() {
return {next : () => ({value : undefined, done : true})};
};
str[Symbol.iterator] = iterator_fn;
// This shouldn't invalidate the protector, because it doesn't support String
// objects.
assertTrue(%StringIteratorProtector());
assertEquals([], [...str]);
var str2 = new String('ott');
assertEquals(['o', 't', 't'], [...str2]);
// This changes the String prototype. No more tests should be run after this in
// the same instance.
str2.__proto__[Symbol.iterator] = iterator_fn;
assertFalse(%StringIteratorProtector());
assertEquals([], [...str2]);