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