@reactivex/rxjs
Version:
Reactive Extensions for modern JavaScript
18 lines (17 loc) • 975 B
TypeScript
import { Observable } from '../Observable';
/**
* Returns an Observable that emits the item at the specified index in the source Observable.
* If default is given, missing indices will output this value on next; otherwise, outputs error.
* @throws {ArgumentOutOfRangeError} When using `elementAt(i)`, it delivers an
* ArgumentOutOrRangeError to the Observer's `error` callback if `i < 0` or the
* Observable has completed before emitting the i-th `next` notification.
* @param {number} index the index of the value to be retrieved.
* @param {any} [defaultValue] the default value returned for missing indices.
* @return {Observable} an Observable that emits a single item, if it is found. Otherwise, will emit the default value if given.
* @method elementAt
* @owner Observable
*/
export declare function elementAt<T>(index: number, defaultValue?: T): Observable<T>;
export interface ElementAtSignature<T> {
(index: number, defaultValue?: T): Observable<T>;
}