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1import { AsyncIterableX } from './asynciterablex';
2import { identityAsync } from '../internal/identity';
3import { returnAsyncIterator } from '../internal/returniterator';
4export class ZipAsyncIterable extends AsyncIterableX {
5 constructor(sources, fn) {
6 super();
7 this._sources = sources;
8 this._fn = fn;
9 }
10 async *[Symbol.asyncIterator]() {
11 const fn = this._fn;
12 const sourcesLength = this._sources.length;
13 const its = this._sources.map(x => x[Symbol.asyncIterator]());
14 do {
15 const values = new Array(sourcesLength);
16 for (let i = -1; ++i < sourcesLength;) {
17 const result = await its[i].next();
18 if (result.done) {
19 await Promise.all(its.map(returnAsyncIterator));
20 return undefined;
21 }
22 values[i] = result.value;
23 }
24 yield await fn(values);
25 } while (1);
26 }
27}
28/* tslint:enable:max-line-length */
29export function zip(...sources) {
30 let fn = sources.shift();
31 if (typeof fn !== 'function') {
32 sources.unshift(fn);
33 fn = identityAsync;
34 }
35 return new ZipAsyncIterable(sources, fn);
36}
37
38//# sourceMappingURL=zip.mjs.map