You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
36 lines
1.6 KiB
36 lines
1.6 KiB
import { Observable } from '../Observable'; |
|
/** |
|
* Emits only the index of the first value emitted by the source Observable that |
|
* meets some condition. |
|
* |
|
* <span class="informal">It's like {@link find}, but emits the index of the |
|
* found value, not the value itself.</span> |
|
* |
|
* <img src="./img/findIndex.png" width="100%"> |
|
* |
|
* `findIndex` searches for the first item in the source Observable that matches |
|
* the specified condition embodied by the `predicate`, and returns the |
|
* (zero-based) index of the first occurrence in the source. Unlike |
|
* {@link first}, the `predicate` is required in `findIndex`, and does not emit |
|
* an error if a valid value is not found. |
|
* |
|
* @example <caption>Emit the index of first click that happens on a DIV element</caption> |
|
* var clicks = Rx.Observable.fromEvent(document, 'click'); |
|
* var result = clicks.findIndex(ev => ev.target.tagName === 'DIV'); |
|
* result.subscribe(x => console.log(x)); |
|
* |
|
* @see {@link filter} |
|
* @see {@link find} |
|
* @see {@link first} |
|
* @see {@link take} |
|
* |
|
* @param {function(value: T, index: number, source: Observable<T>): boolean} predicate |
|
* A function called with each item to test for condition matching. |
|
* @param {any} [thisArg] An optional argument to determine the value of `this` |
|
* in the `predicate` function. |
|
* @return {Observable} An Observable of the index of the first item that |
|
* matches the condition. |
|
* @method find |
|
* @owner Observable |
|
*/ |
|
export declare function findIndex<T>(this: Observable<T>, predicate: (value: T, index: number, source: Observable<T>) => boolean, thisArg?: any): Observable<number>;
|
|
|