@reactivex/ix-es2015-cjs/asynciterable/race.js

The Interactive Extensions for JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.race = exports.RaceAsyncIterable = void 0;
const tslib_1 = require("tslib");
const asynciterablex_js_1 = require("./asynciterablex.js");
const withabort_js_1 = require("./operators/withabort.js");
const aborterror_js_1 = require("../aborterror.js");
const safeRace_js_1 = require("../util/safeRace.js");
function wrapPromiseWithIndex(promise, index) {
    return promise.then((value) => ({ value, index }));
}
/** @ignore */
class RaceAsyncIterable extends asynciterablex_js_1.AsyncIterableX {
    constructor(sources) {
        super();
        this._sources = sources;
    }
    [Symbol.asyncIterator](signal) {
        return tslib_1.__asyncGenerator(this, arguments, function* _a() {
            (0, aborterror_js_1.throwIfAborted)(signal);
            const sources = this._sources;
            const length = sources.length;
            const iterators = new Array(length);
            const nexts = new Array(length);
            for (let i = 0; i < length; i++) {
                const iterator = (0, withabort_js_1.wrapWithAbort)(sources[i], signal)[Symbol.asyncIterator]();
                iterators[i] = iterator;
                nexts[i] = wrapPromiseWithIndex(iterator.next(), i);
            }
            const next = (0, safeRace_js_1.safeRace)(nexts);
            const { value: next$, index } = yield tslib_1.__await(next);
            if (!next$.done) {
                yield yield tslib_1.__await(next$.value);
            }
            const iterator$ = iterators[index];
            // Cancel/finish other iterators
            for (let i = 0; i < length; i++) {
                if (i === index) {
                    continue;
                }
                const otherIterator = iterators[i];
                if (otherIterator.return) {
                    otherIterator.return();
                }
            }
            let nextItem;
            while (!(nextItem = yield tslib_1.__await(iterator$.next())).done) {
                yield yield tslib_1.__await(nextItem.value);
            }
        });
    }
}
exports.RaceAsyncIterable = RaceAsyncIterable;
/**
 * Propagates the async sequence that reacts first.
 *
 * @param {...AsyncIterable<T>[]} sources The source sequences.
 * @return {AsyncIterable<T>} An async sequence that surfaces either of the given sequences, whichever reacted first.
 */
function race(...sources) {
    return new RaceAsyncIterable(sources);
}
exports.race = race;

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