35 lines
1.1 KiB
JavaScript
35 lines
1.1 KiB
JavaScript
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// Copyright 2014 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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// Note: concat does not currently support species so there is no difference
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// between [].concat(foo) and Array.prototype.concat.apply(foo).
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var log = [];
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var logger = {};
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var handler = new Proxy({}, logger);
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logger.get = function(t, trap, r) {
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return function(...args) {
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log.push([trap, ...args]);
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return Reflect[trap](...args);
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}
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};
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var target = ["a", "b"];
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target[Symbol.isConcatSpreadable] = "";
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var obj = new Proxy(target, handler);
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log.length = 0;
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assertEquals([obj], [].concat(obj));
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assertEquals(1, log.length);
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for (var i in log) assertSame(target, log[i][1]);
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assertEquals(["get", target, Symbol.isConcatSpreadable, obj], log[0]);
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log.length = 0;
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assertEquals([obj], Array.prototype.concat.apply(obj));
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assertEquals(2, log.length); // An extra read for the constructor
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for (var i in log) assertSame(target, log[i][1]);
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assertEquals(["get", target, "constructor", obj], log[0]);
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assertEquals(["get", target, Symbol.isConcatSpreadable, obj], log[1]);
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