50 lines
2.3 KiB
JavaScript
50 lines
2.3 KiB
JavaScript
|
import { not } from '../util/not';
|
||
|
|
import { filter } from './filter';
|
||
|
|
/**
|
||
|
|
* Splits the source Observable into two, one with values that satisfy a
|
||
|
|
* predicate, and another with values that don't satisfy the predicate.
|
||
|
|
*
|
||
|
|
* <span class="informal">It's like {@link filter}, but returns two Observables:
|
||
|
|
* one like the output of {@link filter}, and the other with values that did not
|
||
|
|
* pass the condition.</span>
|
||
|
|
*
|
||
|
|
* <img src="./img/partition.png" width="100%">
|
||
|
|
*
|
||
|
|
* `partition` outputs an array with two Observables that partition the values
|
||
|
|
* from the source Observable through the given `predicate` function. The first
|
||
|
|
* Observable in that array emits source values for which the predicate argument
|
||
|
|
* returns true. The second Observable emits source values for which the
|
||
|
|
* predicate returns false. The first behaves like {@link filter} and the second
|
||
|
|
* behaves like {@link filter} with the predicate negated.
|
||
|
|
*
|
||
|
|
* @example <caption>Partition click events into those on DIV elements and those elsewhere</caption>
|
||
|
|
* var clicks = Rx.Observable.fromEvent(document, 'click');
|
||
|
|
* var parts = clicks.partition(ev => ev.target.tagName === 'DIV');
|
||
|
|
* var clicksOnDivs = parts[0];
|
||
|
|
* var clicksElsewhere = parts[1];
|
||
|
|
* clicksOnDivs.subscribe(x => console.log('DIV clicked: ', x));
|
||
|
|
* clicksElsewhere.subscribe(x => console.log('Other clicked: ', x));
|
||
|
|
*
|
||
|
|
* @see {@link filter}
|
||
|
|
*
|
||
|
|
* @param {function(value: T, index: number): boolean} predicate A function that
|
||
|
|
* evaluates each value emitted by the source Observable. If it returns `true`,
|
||
|
|
* the value is emitted on the first Observable in the returned array, if
|
||
|
|
* `false` the value is emitted on the second Observable in the array. The
|
||
|
|
* `index` parameter is the number `i` for the i-th source emission that has
|
||
|
|
* happened since the subscription, starting from the number `0`.
|
||
|
|
* @param {any} [thisArg] An optional argument to determine the value of `this`
|
||
|
|
* in the `predicate` function.
|
||
|
|
* @return {[Observable<T>, Observable<T>]} An array with two Observables: one
|
||
|
|
* with values that passed the predicate, and another with values that did not
|
||
|
|
* pass the predicate.
|
||
|
|
* @method partition
|
||
|
|
* @owner Observable
|
||
|
|
*/
|
||
|
|
export function partition(predicate, thisArg) {
|
||
|
|
return (source) => [
|
||
|
|
filter(predicate, thisArg)(source),
|
||
|
|
filter(not(predicate, thisArg))(source)
|
||
|
|
];
|
||
|
|
}
|
||
|
|
//# sourceMappingURL=partition.js.map
|