blob: 9bd676876bfb2a53103608d2877fcb8167f27ea8 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
|
import { Observable } from '../Observable';
import { MonoTypeOperatorFunction } from '../types';
/**
* 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
* items, notify of an IllegalArgumentException or NoSuchElementException respectively. If the source Observable
* emits items but none match the specified predicate then `undefined` is emitted.
*
* ![](single.png)
*
* @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 or `undefined` when no items match.
*
* @method single
* @owner Observable
*/
export declare function single<T>(predicate?: (value: T, index: number, source: Observable<T>) => boolean): MonoTypeOperatorFunction<T>;
|