1 | 'use strict';
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2 | // https://github.com/tc39/proposal-iterator-helpers
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3 | var $ = require('../internals/export');
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4 | var aFunction = require('../internals/a-function');
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5 | var anObject = require('../internals/an-object');
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6 | var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
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7 |
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8 | var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
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9 | var state = this;
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10 | var filterer = state.filterer;
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11 |
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12 | return new Promise(function (resolve, reject) {
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13 | var loop = function () {
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14 | try {
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15 | Promise.resolve(anObject(state.next.call(state.iterator, arg))).then(function (step) {
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16 | try {
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17 | if (anObject(step).done) {
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18 | state.done = true;
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19 | resolve({ done: true, value: undefined });
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20 | } else {
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21 | var value = step.value;
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22 | Promise.resolve(filterer(value)).then(function (selected) {
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23 | selected ? resolve({ done: false, value: value }) : loop();
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24 | }, reject);
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25 | }
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26 | } catch (err) { reject(err); }
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27 | }, reject);
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28 | } catch (error) { reject(error); }
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29 | };
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30 |
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31 | loop();
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32 | });
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33 | });
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34 |
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35 | $({ target: 'AsyncIterator', proto: true, real: true }, {
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36 | filter: function filter(filterer) {
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37 | return new AsyncIteratorProxy({
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38 | iterator: anObject(this),
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39 | filterer: aFunction(filterer)
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40 | });
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41 | }
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42 | });
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