1 | import { identityAsync } from '../util/identity';
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2 | import { bindCallback } from '../util/bindcallback';
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3 | import { isIterable, isAsyncIterable, isArrayLike, isIterator, isPromise, isObservable } from '../util/isiterable';
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4 | import { toLength } from '../util/tolength';
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5 | import { AsyncSink } from './asyncsink';
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6 | export let from;
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7 | export let FromArrayIterable;
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8 | export let FromAsyncIterable;
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9 | export let FromPromiseIterable;
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10 | export let FromObservableAsyncIterable;
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11 | export function _initialize(Ctor) {
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12 |
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13 | from = function (source, selector = identityAsync, thisArg) {
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14 | const fn = bindCallback(selector, thisArg, 2);
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15 | if (isIterable(source) || isAsyncIterable(source)) {
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16 | return new FromAsyncIterable(source, fn);
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17 | }
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18 | if (isPromise(source)) {
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19 | return new FromPromiseIterable(source, fn);
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20 | }
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21 | if (isObservable(source)) {
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22 | return new FromObservableAsyncIterable(source, fn);
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23 | }
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24 | if (isArrayLike(source)) {
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25 | return new FromArrayIterable(source, fn);
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26 | }
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27 | if (isIterator(source)) {
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28 | return new FromAsyncIterable({ [Symbol.asyncIterator]: () => source }, fn);
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29 | }
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30 | throw new TypeError('Input type not supported');
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31 | };
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32 |
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33 | FromArrayIterable = class FromArrayIterable extends Ctor {
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34 | constructor(source, selector) {
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35 | super();
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36 | this._source = source;
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37 | this._selector = selector;
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38 | }
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39 | async *[Symbol.asyncIterator]() {
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40 | let i = 0;
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41 | const length = toLength(this._source.length);
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42 | while (i < length) {
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43 | yield await this._selector(this._source[i], i++);
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44 | }
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45 | }
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46 | };
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47 |
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48 | FromAsyncIterable = class FromAsyncIterable extends Ctor {
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49 | constructor(source, selector) {
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50 | super();
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51 | this._source = source;
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52 | this._selector = selector;
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53 | }
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54 | async *[Symbol.asyncIterator]() {
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55 | let i = 0;
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56 | for await (const item of this._source) {
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57 | yield await this._selector(item, i++);
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58 | }
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59 | }
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60 | };
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61 |
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62 | FromPromiseIterable = class FromPromiseIterable extends Ctor {
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63 | constructor(source, selector) {
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64 | super();
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65 | this._source = source;
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66 | this._selector = selector;
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67 | }
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68 | async *[Symbol.asyncIterator]() {
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69 | const item = await this._source;
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70 | yield await this._selector(item, 0);
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71 | }
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72 | };
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73 |
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74 | FromObservableAsyncIterable = class FromObservableAsyncIterable extends Ctor {
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75 | constructor(observable, selector) {
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76 | super();
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77 | this._observable = observable;
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78 | this._selector = selector;
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79 | }
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80 | async *[Symbol.asyncIterator]() {
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81 | const sink = new AsyncSink();
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82 | const subscription = this._observable.subscribe({
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83 | next(value) {
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84 | sink.write(value);
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85 | },
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86 | error(err) {
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87 | sink.error(err);
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88 | },
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89 | complete() {
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90 | sink.end();
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91 | }
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92 | });
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93 | let i = 0;
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94 | try {
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95 | for (let next; !(next = await sink.next()).done;) {
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96 | yield await this._selector(next.value, i++);
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97 | }
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98 | }
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99 | finally {
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100 | subscription.unsubscribe();
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101 | }
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102 | }
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103 | };
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104 | }
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105 |
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106 |
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