41 lines
1.8 KiB
JavaScript
41 lines
1.8 KiB
JavaScript
import { takeWhile as higherOrder } from '../operators/takeWhile';
|
|
/**
|
|
* Emits values emitted by the source Observable so long as each value satisfies
|
|
* the given `predicate`, and then completes as soon as this `predicate` is not
|
|
* satisfied.
|
|
*
|
|
* <span class="informal">Takes values from the source only while they pass the
|
|
* condition given. When the first value does not satisfy, it completes.</span>
|
|
*
|
|
* <img src="./img/takeWhile.png" width="100%">
|
|
*
|
|
* `takeWhile` subscribes and begins mirroring the source Observable. Each value
|
|
* emitted on the source is given to the `predicate` function which returns a
|
|
* boolean, representing a condition to be satisfied by the source values. The
|
|
* output Observable emits the source values until such time as the `predicate`
|
|
* returns false, at which point `takeWhile` stops mirroring the source
|
|
* Observable and completes the output Observable.
|
|
*
|
|
* @example <caption>Emit click events only while the clientX property is greater than 200</caption>
|
|
* var clicks = Rx.Observable.fromEvent(document, 'click');
|
|
* var result = clicks.takeWhile(ev => ev.clientX > 200);
|
|
* result.subscribe(x => console.log(x));
|
|
*
|
|
* @see {@link take}
|
|
* @see {@link takeLast}
|
|
* @see {@link takeUntil}
|
|
* @see {@link skip}
|
|
*
|
|
* @param {function(value: T, index: number): boolean} predicate A function that
|
|
* evaluates a value emitted by the source Observable and returns a boolean.
|
|
* Also takes the (zero-based) index as the second argument.
|
|
* @return {Observable<T>} An Observable that emits the values from the source
|
|
* Observable so long as each value satisfies the condition defined by the
|
|
* `predicate`, then completes.
|
|
* @method takeWhile
|
|
* @owner Observable
|
|
*/
|
|
export function takeWhile(predicate) {
|
|
return higherOrder(predicate)(this);
|
|
}
|
|
//# sourceMappingURL=takeWhile.js.map
|