e13f2ff40b
Previous changes with subclassable builtins and @@species were a bit aggressive in making TypedArray.prototype.subarray act like the ES2016 specification in terms of returning an instance of the subclass as a result. It turns out that Node.js, and extracted libraries for the web, subclass TypedArrays but don't expect the subclass constructor to be called by subarray. @@species will provide an escape hatch, but it has not shipped yet, and will take some time for uptake by libraries. For now, this patch makes TypedArray.prototype.subarray fall back to constructing an instance of the parent TypedArray class, such as Uint8Array. R=adamk LOG=Y BUG=v8:4665 Review URL: https://codereview.chromium.org/1583773005 Cr-Commit-Position: refs/heads/master@{#33312}
39 lines
1.4 KiB
JavaScript
39 lines
1.4 KiB
JavaScript
// Copyright 2015 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: --noharmony-species
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// Before Symbol.species was added, ArrayBuffer subclasses constructed
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// ArrayBuffers, and Array subclasses constructed Arrays, but TypedArray and
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// Promise subclasses constructed an instance of the subclass.
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'use strict';
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assertEquals(undefined, Symbol.species);
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class MyArray extends Array { }
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let myArray = new MyArray();
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assertEquals(MyArray, myArray.constructor);
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assertEquals(Array, myArray.map(x => x + 1).constructor);
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assertEquals(Array, myArray.concat().constructor);
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class MyUint8Array extends Uint8Array { }
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Object.defineProperty(MyUint8Array.prototype, "BYTES_PER_ELEMENT", {value: 1});
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let myTypedArray = new MyUint8Array(3);
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assertEquals(MyUint8Array, myTypedArray.constructor);
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assertEquals(MyUint8Array, myTypedArray.map(x => x + 1).constructor);
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class MyArrayBuffer extends ArrayBuffer { }
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let myBuffer = new MyArrayBuffer(0);
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assertEquals(MyArrayBuffer, myBuffer.constructor);
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assertEquals(ArrayBuffer, myBuffer.slice().constructor);
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class MyPromise extends Promise { }
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let myPromise = new MyPromise(() => {});
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assertEquals(MyPromise, myPromise.constructor);
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assertEquals(MyPromise, myPromise.then().constructor);
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// However, subarray instantiates members of the parent class
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assertEquals(Uint8Array, myTypedArray.subarray(1).constructor);
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