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add shareLast operator

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This commit is contained in:
Dan Percic 2021-11-06 02:02:49 +02:00
parent 1df1b1ab89
commit e1ce89e38d
1 changed files with 6 additions and 2 deletions
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8
src/lib/utils/operators.ts
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@ -1,5 +1,5 @@
import { distinctUntilChanged, map } from 'rxjs/operators';
import { OperatorFunction, pipe } from 'rxjs';
import { distinctUntilChanged, map, shareReplay } from 'rxjs/operators';
import { MonoTypeOperatorFunction, OperatorFunction, pipe } from 'rxjs';
export function get<T>(predicate: (value: T, index: number) => boolean): OperatorFunction<readonly T[], T | undefined> {
return map(entities => entities.find(predicate));
@ -17,5 +17,9 @@ export function filterEach<T>(predicate: (value: T, index: number) => boolean):
return map(entities => entities.filter(predicate));
}
export function shareLast<T>(values = 1): MonoTypeOperatorFunction<T> {
return shareReplay<T>({ bufferSize: values, refCount: true });
}
export const toLengthValue = (entities: unknown[]): number => entities?.length ?? 0;
export const getLength = pipe(map(toLengthValue), distinctUntilChanged());