work.suroh.tk/node_modules/rxjs/operators/single.d.ts

20 lines
1.0 KiB
TypeScript

import { Observable } from '../Observable';
import { MonoTypeOperatorFunction } from '../interfaces';
/**
* Returns an Observable that emits the single item emitted by the source Observable that matches a specified
* predicate, if that Observable emits one such item. If the source Observable emits more than one such item or no
* such items, notify of an IllegalArgumentException or NoSuchElementException respectively.
*
* <img src="./img/single.png" width="100%">
*
* @throws {EmptyError} Delivers an EmptyError to the Observer's `error`
* callback if the Observable completes before any `next` notification was sent.
* @param {Function} predicate - A predicate function to evaluate items emitted by the source Observable.
* @return {Observable<T>} An Observable that emits the single item emitted by the source Observable that matches
* the predicate.
.
* @method single
* @owner Observable
*/
export declare function single<T>(predicate?: (value: T, index: number, source: Observable<T>) => boolean): MonoTypeOperatorFunction<T>;