1 | import { AsyncIterableX } from './asynciterablex';
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2 | import { identity } from '../util/identity';
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3 | import { wrapWithAbort } from './operators/withabort';
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4 | import { throwIfAborted } from '../aborterror';
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5 |
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6 | const NEVER_PROMISE = new Promise(() => { });
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7 | function wrapPromiseWithIndex(promise, index) {
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8 | return promise.then((value) => ({ value, index }));
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9 | }
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10 | export class CombineLatestAsyncIterable extends AsyncIterableX {
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11 | constructor(sources) {
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12 | super();
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13 | this._sources = sources;
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14 | }
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15 | async *[Symbol.asyncIterator](signal) {
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16 | throwIfAborted(signal);
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17 | const length = this._sources.length;
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18 | const iterators = new Array(length);
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19 | const nexts = new Array(length);
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20 | let hasValueAll = false;
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21 | const values = new Array(length);
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22 | const hasValues = new Array(length);
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23 | let active = length;
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24 | hasValues.fill(false);
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25 | for (let i = 0; i < length; i++) {
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26 | const iterator = wrapWithAbort(this._sources[i], signal)[Symbol.asyncIterator]();
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27 | iterators[i] = iterator;
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28 | nexts[i] = wrapPromiseWithIndex(iterator.next(), i);
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29 | }
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30 | while (active > 0) {
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31 | const next = Promise.race(nexts);
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32 | const { value: { value: value$, done: done$ }, index, } = await next;
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33 | if (done$) {
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34 | nexts[index] = NEVER_PROMISE;
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35 | active--;
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36 | }
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37 | else {
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38 | values[index] = value$;
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39 | hasValues[index] = true;
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40 | const iterator$ = iterators[index];
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41 | nexts[index] = wrapPromiseWithIndex(iterator$.next(), index);
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42 | if (hasValueAll || (hasValueAll = hasValues.every(identity))) {
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43 | yield values;
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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 | }
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49 | export function combineLatest(...sources) {
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50 | return new CombineLatestAsyncIterable(sources);
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51 | }
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52 |
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53 |
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