mirror of https://github.com/tc39/test262.git
54 lines
1.3 KiB
JavaScript
54 lines
1.3 KiB
JavaScript
// Copyright (C) 2023 Michael Ficarra. All rights reserved.
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// This code is governed by the BSD license found in the LICENSE file.
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/*---
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esid: sec-iterator.from
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description: >
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Iterator.from does not respect the iterability of any primitive except Strings
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info: |
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Iterator.from ( O )
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1. If O is a String, set O to ! ToObject(O).
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2. Let iteratorRecord be ? GetIteratorFlattenable(O).
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includes: [compareArray.js]
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features: [iterator-helpers]
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flags: []
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---*/
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function* g() {
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yield 0;
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}
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Number.prototype[Symbol.iterator] = function* () {
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let i = 0;
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let target = this >>> 0;
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while (i < target) {
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yield i;
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++i;
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}
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};
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assert.compareArray(Array.from(5), [0, 1, 2, 3, 4]);
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assert.throws(TypeError, function () {
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Iterator.from(5);
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});
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assert.compareArray(Array.from(Iterator.from(new Number(5))), [0, 1, 2, 3, 4]);
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assert.compareArray(Array.from(Iterator.from('string')), ['s', 't', 'r', 'i', 'n', 'g']);
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const originalStringIterator = String.prototype[Symbol.iterator];
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let observedType;
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Object.defineProperty(String.prototype, Symbol.iterator, {
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get() {
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'use strict';
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observedType = typeof this;
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return originalStringIterator;
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}
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});
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Iterator.from('');
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assert.sameValue(observedType, 'string');
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Iterator.from(new String(''));
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assert.sameValue(observedType, 'object');
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