28 lines
849 B
JavaScript
28 lines
849 B
JavaScript
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'use strict';
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// https://github.com/tc39/proposal-iterator-helpers
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var $ = require('../internals/export');
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var anObject = require('../internals/an-object');
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var createAsyncIteratorProxy = require('../internals/create-async-iterator-proxy');
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
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var state = this;
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var iterator = state.iterator;
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return Promise.resolve(anObject(state.next.call(iterator, arg))).then(function (step) {
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if (anObject(step).done) {
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state.done = true;
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return { done: true, value: undefined };
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}
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return { done: false, value: [state.index++, step.value] };
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});
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});
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$({ target: 'AsyncIterator', proto: true, real: true }, {
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asIndexedPairs: function asIndexedPairs() {
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return new AsyncIteratorProxy({
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iterator: anObject(this),
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index: 0
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});
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}
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});
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