55 lines
2.3 KiB
TypeScript
55 lines
2.3 KiB
TypeScript
import { ObservableInput } from '../types';
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import { Observable } from '../Observable';
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/**
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* Splits the source Observable into two, one with values that satisfy a
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* predicate, and another with values that don't satisfy the predicate.
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*
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* <span class="informal">It's like {@link filter}, but returns two Observables:
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* one like the output of {@link filter}, and the other with values that did not
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* pass the condition.</span>
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*
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* 
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*
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* `partition` outputs an array with two Observables that partition the values
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* from the source Observable through the given `predicate` function. The first
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* Observable in that array emits source values for which the predicate argument
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* returns true. The second Observable emits source values for which the
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* predicate returns false. The first behaves like {@link filter} and the second
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* behaves like {@link filter} with the predicate negated.
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*
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* ## Example
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* Partition a set of numbers into odds and evens observables
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* ```ts
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* import { of, partition } from 'rxjs';
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*
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* const observableValues = of(1, 2, 3, 4, 5, 6);
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* const [evens$, odds$] = partition(observableValues, (value, index) => value % 2 === 0);
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*
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* odds$.subscribe(x => console.log('odds', x));
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* evens$.subscribe(x => console.log('evens', x));
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*
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* // Logs:
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* // odds 1
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* // odds 3
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* // odds 5
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* // evens 2
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* // evens 4
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* // evens 6
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* ```
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*
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* @see {@link filter}
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*
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* @param {function(value: T, index: number): boolean} predicate A function that
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* evaluates each value emitted by the source Observable. If it returns `true`,
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* the value is emitted on the first Observable in the returned array, if
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* `false` the value is emitted on the second Observable in the array. The
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* `index` parameter is the number `i` for the i-th source emission that has
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* happened since the subscription, starting from the number `0`.
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* @param {any} [thisArg] An optional argument to determine the value of `this`
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* in the `predicate` function.
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* @return {[Observable<T>, Observable<T>]} An array with two Observables: one
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* with values that passed the predicate, and another with values that did not
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* pass the predicate.
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*/
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export declare function partition<T>(source: ObservableInput<T>, predicate: (value: T, index: number) => boolean, thisArg?: any): [Observable<T>, Observable<T>];
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