[6a3a178] | 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 getIteratorMethod = require('../internals/get-iterator-method');
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| 7 | var createIteratorProxy = require('../internals/iterator-create-proxy');
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| 8 | var iteratorClose = require('../internals/iterator-close');
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| 9 |
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| 10 | var IteratorProxy = createIteratorProxy(function (arg) {
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| 11 | var iterator = this.iterator;
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| 12 | var mapper = this.mapper;
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| 13 | var result, mapped, iteratorMethod, innerIterator;
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| 14 |
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| 15 | while (true) {
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| 16 | try {
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| 17 | if (innerIterator = this.innerIterator) {
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| 18 | result = anObject(this.innerNext.call(innerIterator));
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| 19 | if (!result.done) return result.value;
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| 20 | this.innerIterator = this.innerNext = null;
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| 21 | }
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| 22 |
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| 23 | result = anObject(this.next.call(iterator, arg));
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| 24 |
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| 25 | if (this.done = !!result.done) return;
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| 26 |
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| 27 | mapped = mapper(result.value);
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| 28 | iteratorMethod = getIteratorMethod(mapped);
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| 29 |
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| 30 | if (iteratorMethod === undefined) {
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| 31 | throw TypeError('.flatMap callback should return an iterable object');
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| 32 | }
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| 33 |
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| 34 | this.innerIterator = innerIterator = anObject(iteratorMethod.call(mapped));
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| 35 | this.innerNext = aFunction(innerIterator.next);
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| 36 | } catch (error) {
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| 37 | iteratorClose(iterator);
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| 38 | throw error;
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| 39 | }
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| 40 | }
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| 41 | });
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| 42 |
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| 43 | $({ target: 'Iterator', proto: true, real: true }, {
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| 44 | flatMap: function flatMap(mapper) {
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| 45 | return new IteratorProxy({
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| 46 | iterator: anObject(this),
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| 47 | mapper: aFunction(mapper),
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| 48 | innerIterator: null,
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| 49 | innerNext: null
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| 50 | });
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| 51 | }
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| 52 | });
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