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
2 years ago
|
import { Observable } from '../Observable';
|
||
|
|
/**
|
||
|
|
* Applies a given `project` function to each value emitted by the source
|
||
|
|
* Observable, and emits the resulting values as an Observable.
|
||
|
|
*
|
||
|
|
* <span class="informal">Like [Array.prototype.map()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map),
|
||
|
|
* it passes each source value through a transformation function to get
|
||
|
|
* corresponding output values.</span>
|
||
|
|
*
|
||
|
|
* <img src="./img/map.png" width="100%">
|
||
|
|
*
|
||
|
|
* Similar to the well known `Array.prototype.map` function, this operator
|
||
|
|
* applies a projection to each value and emits that projection in the output
|
||
|
|
* Observable.
|
||
|
|
*
|
||
|
|
* @example <caption>Map every click to the clientX position of that click</caption>
|
||
|
|
* var clicks = Rx.Observable.fromEvent(document, 'click');
|
||
|
|
* var positions = clicks.map(ev => ev.clientX);
|
||
|
|
* positions.subscribe(x => console.log(x));
|
||
|
|
*
|
||
|
|
* @see {@link mapTo}
|
||
|
|
* @see {@link pluck}
|
||
|
|
*
|
||
|
|
* @param {function(value: T, index: number): R} project The function to apply
|
||
|
|
* to each `value` emitted by the source Observable. The `index` parameter is
|
||
|
|
* the number `i` for the i-th emission that has happened since the
|
||
|
|
* subscription, starting from the number `0`.
|
||
|
|
* @param {any} [thisArg] An optional argument to define what `this` is in the
|
||
|
|
* `project` function.
|
||
|
|
* @return {Observable<R>} An Observable that emits the values from the source
|
||
|
|
* Observable transformed by the given `project` function.
|
||
|
|
* @method map
|
||
|
|
* @owner Observable
|
||
|
|
*/
|
||
|
|
export declare function map<T, R>(this: Observable<T>, project: (value: T, index: number) => R, thisArg?: any): Observable<R>;
|