49 lines
1.7 KiB
JavaScript
49 lines
1.7 KiB
JavaScript
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'use strict';
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var $ = require('../internals/export');
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var call = require('../internals/function-call');
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var anObject = require('../internals/an-object');
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var getIteratorDirect = require('../internals/get-iterator-direct');
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var notANaN = require('../internals/not-a-nan');
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var toPositiveInteger = require('../internals/to-positive-integer');
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var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
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var createIterResultObject = require('../internals/create-iter-result-object');
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var IS_PURE = require('../internals/is-pure');
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
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var state = this;
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var iterator = state.iterator;
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var returnMethod;
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if (!state.remaining--) {
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var resultDone = createIterResultObject(undefined, true);
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state.done = true;
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returnMethod = iterator['return'];
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if (returnMethod !== undefined) {
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return Promise.resolve(call(returnMethod, iterator, undefined)).then(function () {
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return resultDone;
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});
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}
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return resultDone;
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} return Promise.resolve(call(state.next, iterator)).then(function (step) {
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if (anObject(step).done) {
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state.done = true;
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return createIterResultObject(undefined, true);
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} return createIterResultObject(step.value, false);
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}).then(null, function (error) {
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state.done = true;
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throw error;
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});
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});
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// `AsyncIterator.prototype.take` method
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// https://github.com/tc39/proposal-async-iterator-helpers
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$({ target: 'AsyncIterator', proto: true, real: true, forced: IS_PURE }, {
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take: function take(limit) {
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anObject(this);
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var remaining = toPositiveInteger(notANaN(+limit));
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return new AsyncIteratorProxy(getIteratorDirect(this), {
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remaining: remaining
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});
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}
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});
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