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43 lines
1.3 KiB
43 lines
1.3 KiB
3 years ago
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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 aFunction = require('../internals/a-function');
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var anObject = require('../internals/an-object');
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var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
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var state = this;
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var filterer = state.filterer;
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return new Promise(function (resolve, reject) {
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var loop = function () {
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try {
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Promise.resolve(anObject(state.next.call(state.iterator, arg))).then(function (step) {
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try {
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if (anObject(step).done) {
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state.done = true;
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resolve({ done: true, value: undefined });
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} else {
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var value = step.value;
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Promise.resolve(filterer(value)).then(function (selected) {
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selected ? resolve({ done: false, value: value }) : loop();
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}, reject);
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}
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} catch (err) { reject(err); }
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}, reject);
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} catch (error) { reject(error); }
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};
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loop();
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});
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});
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$({ target: 'AsyncIterator', proto: true, real: true }, {
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filter: function filter(filterer) {
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return new AsyncIteratorProxy({
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iterator: anObject(this),
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filterer: aFunction(filterer)
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});
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}
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});
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