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- import { OperatorFunction, ObservableInputTuple } from '../types';
- import { raceInit } from '../observable/race';
- import { operate } from '../util/lift';
- import { identity } from '../util/identity';
- /**
- * Creates an Observable that mirrors the first source Observable to emit a next,
- * error or complete notification from the combination of the Observable to which
- * the operator is applied and supplied Observables.
- *
- * ## Example
- *
- * ```ts
- * import { interval, map, raceWith } from 'rxjs';
- *
- * const obs1 = interval(7000).pipe(map(() => 'slow one'));
- * const obs2 = interval(3000).pipe(map(() => 'fast one'));
- * const obs3 = interval(5000).pipe(map(() => 'medium one'));
- *
- * obs1
- * .pipe(raceWith(obs2, obs3))
- * .subscribe(winner => console.log(winner));
- *
- * // Outputs
- * // a series of 'fast one'
- * ```
- *
- * @param otherSources Sources used to race for which Observable emits first.
- * @return A function that returns an Observable that mirrors the output of the
- * first Observable to emit an item.
- */
- export function raceWith<T, A extends readonly unknown[]>(
- ...otherSources: [...ObservableInputTuple<A>]
- ): OperatorFunction<T, T | A[number]> {
- return !otherSources.length
- ? identity
- : operate((source, subscriber) => {
- raceInit<T | A[number]>([source, ...otherSources])(subscriber);
- });
- }
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