'use strict';
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var fails = require('../internals/fails');
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var isCallable = require('../internals/is-callable');
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var create = require('../internals/object-create');
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var getPrototypeOf = require('../internals/object-get-prototype-of');
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var defineBuiltIn = require('../internals/define-built-in');
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var wellKnownSymbol = require('../internals/well-known-symbol');
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var IS_PURE = require('../internals/is-pure');
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var ITERATOR = wellKnownSymbol('iterator');
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var BUGGY_SAFARI_ITERATORS = false;
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// `%IteratorPrototype%` object
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// https://tc39.es/ecma262/#sec-%iteratorprototype%-object
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var IteratorPrototype, PrototypeOfArrayIteratorPrototype, arrayIterator;
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/* eslint-disable es-x/no-array-prototype-keys -- safe */
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if ([].keys) {
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arrayIterator = [].keys();
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// Safari 8 has buggy iterators w/o `next`
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if (!('next' in arrayIterator)) BUGGY_SAFARI_ITERATORS = true;
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else {
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PrototypeOfArrayIteratorPrototype = getPrototypeOf(getPrototypeOf(arrayIterator));
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if (PrototypeOfArrayIteratorPrototype !== Object.prototype) IteratorPrototype = PrototypeOfArrayIteratorPrototype;
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}
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}
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var NEW_ITERATOR_PROTOTYPE = IteratorPrototype == undefined || fails(function () {
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var test = {};
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// FF44- legacy iterators case
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return IteratorPrototype[ITERATOR].call(test) !== test;
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});
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if (NEW_ITERATOR_PROTOTYPE) IteratorPrototype = {};
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else if (IS_PURE) IteratorPrototype = create(IteratorPrototype);
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// `%IteratorPrototype%[@@iterator]()` method
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// https://tc39.es/ecma262/#sec-%iteratorprototype%-@@iterator
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if (!isCallable(IteratorPrototype[ITERATOR])) {
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defineBuiltIn(IteratorPrototype, ITERATOR, function () {
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return this;
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});
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}
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module.exports = {
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IteratorPrototype: IteratorPrototype,
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BUGGY_SAFARI_ITERATORS: BUGGY_SAFARI_ITERATORS
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};
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