29 lines
1.1 KiB
JavaScript
29 lines
1.1 KiB
JavaScript
// https://github.com/tc39/proposal-iterator-helpers
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var $ = require('../internals/export');
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var call = require('../internals/function-call');
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var toObject = require('../internals/to-object');
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var isPrototypeOf = require('../internals/object-is-prototype-of');
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var IteratorPrototype = require('../internals/iterators-core').IteratorPrototype;
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var createIteratorProxy = require('../internals/iterator-create-proxy');
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var getIterator = require('../internals/get-iterator');
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var getIteratorDirect = require('../internals/get-iterator-direct');
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var getIteratorMethod = require('../internals/get-iterator-method');
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var IteratorProxy = createIteratorProxy(function () {
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return call(this.next, this.iterator);
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}, true);
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$({ target: 'Iterator', stat: true, forced: true }, {
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from: function from(O) {
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var object = toObject(O);
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var usingIterator = getIteratorMethod(object);
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var iterator;
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if (usingIterator) {
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iterator = getIterator(object, usingIterator);
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if (isPrototypeOf(IteratorPrototype, iterator)) return iterator;
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} else {
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iterator = object;
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} return new IteratorProxy(getIteratorDirect(iterator));
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}
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});
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