deb7d5b090
This is a rework of the instanceof operator to support ES6 semantics (as per section 12.10.4 of the spec: https://tc39.github.io/ecma262/#sec-instanceofoperator). It's behind flag --harmony-instanceof for now, which is turned on for staging. BUG=v8:4447 LOG=N Review URL: https://codereview.chromium.org/1692713005 Cr-Commit-Position: refs/heads/master@{#34170}
51 lines
1.6 KiB
JavaScript
51 lines
1.6 KiB
JavaScript
// Copyright 2016 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Flags: --harmony-instanceof
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// Make sure it's an error if @@hasInstance isn't a function.
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(function() {
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var F = {};
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F[Symbol.hasInstance] = null;
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assertThrows(function() { 0 instanceof F; }, TypeError);
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})();
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// Make sure the result is coerced to boolean.
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(function() {
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var F = {};
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F[Symbol.hasInstance] = function() { return undefined; };
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assertEquals(0 instanceof F, false);
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F[Symbol.hasInstance] = function() { return null; };
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assertEquals(0 instanceof F, false);
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F[Symbol.hasInstance] = function() { return true; };
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assertEquals(0 instanceof F, true);
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})();
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// Make sure if @@hasInstance throws, we catch it.
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(function() {
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var F = {};
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F[Symbol.hasInstance] = function() { throw new Error("always throws"); }
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try {
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0 instanceof F;
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} catch (e) {
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assertEquals(e.message, "always throws");
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}
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})();
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// @@hasInstance works for bound functions.
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(function() {
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var BC = function() {};
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var bc = new BC();
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var bound = BC.bind();
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assertEquals(bound[Symbol.hasInstance](bc), true);
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assertEquals(bound[Symbol.hasInstance]([]), false);
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})();
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// if OrdinaryHasInstance is passed a non-callable receiver, return false.
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assertEquals(Function.prototype[Symbol.hasInstance].call(Array, []), true);
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assertEquals(Function.prototype[Symbol.hasInstance].call({}, {}), false);
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// OrdinaryHasInstance passed a non-object argument returns false.
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assertEquals(Function.prototype[Symbol.hasInstance].call(Array, 0), false);
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