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

29 lines
1.1 KiB
TypeScript

import { OperatorFunction } from '../interfaces';
/**
* Maps each source value (an object) to its specified nested property.
*
* <span class="informal">Like {@link map}, but meant only for picking one of
* the nested properties of every emitted object.</span>
*
* <img src="./img/pluck.png" width="100%">
*
* Given a list of strings describing a path to an object property, retrieves
* the value of a specified nested property from all values in the source
* Observable. If a property can't be resolved, it will return `undefined` for
* that value.
*
* @example <caption>Map every click to the tagName of the clicked target element</caption>
* var clicks = Rx.Observable.fromEvent(document, 'click');
* var tagNames = clicks.pluck('target', 'tagName');
* tagNames.subscribe(x => console.log(x));
*
* @see {@link map}
*
* @param {...string} properties The nested properties to pluck from each source
* value (an object).
* @return {Observable} A new Observable of property values from the source values.
* @method pluck
* @owner Observable
*/
export declare function pluck<T, R>(...properties: string[]): OperatorFunction<T, R>;