1 | 'use strict';
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2 | var fails = require('../internals/fails');
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3 | var getPrototypeOf = require('../internals/object-get-prototype-of');
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4 | var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
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5 | var has = require('../internals/has');
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6 | var wellKnownSymbol = require('../internals/well-known-symbol');
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7 | var IS_PURE = require('../internals/is-pure');
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8 |
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9 | var ITERATOR = wellKnownSymbol('iterator');
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10 | var BUGGY_SAFARI_ITERATORS = false;
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11 |
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12 | var returnThis = function () { return this; };
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13 |
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14 | // `%IteratorPrototype%` object
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15 | // https://tc39.es/ecma262/#sec-%iteratorprototype%-object
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16 | var IteratorPrototype, PrototypeOfArrayIteratorPrototype, arrayIterator;
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17 |
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18 | /* eslint-disable es/no-array-prototype-keys -- safe */
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19 | if ([].keys) {
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20 | arrayIterator = [].keys();
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21 | // Safari 8 has buggy iterators w/o `next`
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22 | if (!('next' in arrayIterator)) BUGGY_SAFARI_ITERATORS = true;
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23 | else {
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24 | PrototypeOfArrayIteratorPrototype = getPrototypeOf(getPrototypeOf(arrayIterator));
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25 | if (PrototypeOfArrayIteratorPrototype !== Object.prototype) IteratorPrototype = PrototypeOfArrayIteratorPrototype;
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26 | }
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27 | }
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28 |
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29 | var NEW_ITERATOR_PROTOTYPE = IteratorPrototype == undefined || fails(function () {
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30 | var test = {};
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31 | // FF44- legacy iterators case
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32 | return IteratorPrototype[ITERATOR].call(test) !== test;
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33 | });
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34 |
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35 | if (NEW_ITERATOR_PROTOTYPE) IteratorPrototype = {};
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36 |
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37 | // `%IteratorPrototype%[@@iterator]()` method
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38 | // https://tc39.es/ecma262/#sec-%iteratorprototype%-@@iterator
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39 | if ((!IS_PURE || NEW_ITERATOR_PROTOTYPE) && !has(IteratorPrototype, ITERATOR)) {
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40 | createNonEnumerableProperty(IteratorPrototype, ITERATOR, returnThis);
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41 | }
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42 |
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43 | module.exports = {
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44 | IteratorPrototype: IteratorPrototype,
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45 | BUGGY_SAFARI_ITERATORS: BUGGY_SAFARI_ITERATORS
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46 | };
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