From e4fa1e69e7ebfb627c7198fd1a9881e9327ec4d4 Mon Sep 17 00:00:00 2001 From: Pinapelz Date: Sat, 28 Jun 2025 17:26:46 -0700 Subject: initial commit: scaffolding --- node_modules/rxjs/src/internal/operators/reduce.ts | 61 ++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 node_modules/rxjs/src/internal/operators/reduce.ts (limited to 'node_modules/rxjs/src/internal/operators/reduce.ts') diff --git a/node_modules/rxjs/src/internal/operators/reduce.ts b/node_modules/rxjs/src/internal/operators/reduce.ts new file mode 100644 index 0000000..5ee565e --- /dev/null +++ b/node_modules/rxjs/src/internal/operators/reduce.ts @@ -0,0 +1,61 @@ +import { scanInternals } from './scanInternals'; +import { OperatorFunction } from '../types'; +import { operate } from '../util/lift'; + +export function reduce(accumulator: (acc: A | V, value: V, index: number) => A): OperatorFunction; +export function reduce(accumulator: (acc: A, value: V, index: number) => A, seed: A): OperatorFunction; +export function reduce(accumulator: (acc: A | S, value: V, index: number) => A, seed: S): OperatorFunction; + +/** + * Applies an accumulator function over the source Observable, and returns the + * accumulated result when the source completes, given an optional seed value. + * + * Combines together all values emitted on the source, + * using an accumulator function that knows how to join a new source value into + * the accumulation from the past. + * + * ![](reduce.png) + * + * Like + * [Array.prototype.reduce()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce), + * `reduce` applies an `accumulator` function against an accumulation and each + * value of the source Observable (from the past) to reduce it to a single + * value, emitted on the output Observable. Note that `reduce` will only emit + * one value, only when the source Observable completes. It is equivalent to + * applying operator {@link scan} followed by operator {@link last}. + * + * Returns an Observable that applies a specified `accumulator` function to each + * item emitted by the source Observable. If a `seed` value is specified, then + * that value will be used as the initial value for the accumulator. If no seed + * value is specified, the first item of the source is used as the seed. + * + * ## Example + * + * Count the number of click events that happened in 5 seconds + * + * ```ts + * import { fromEvent, takeUntil, interval, map, reduce } from 'rxjs'; + * + * const clicksInFiveSeconds = fromEvent(document, 'click') + * .pipe(takeUntil(interval(5000))); + * + * const ones = clicksInFiveSeconds.pipe(map(() => 1)); + * const seed = 0; + * const count = ones.pipe(reduce((acc, one) => acc + one, seed)); + * + * count.subscribe(x => console.log(x)); + * ``` + * + * @see {@link count} + * @see {@link expand} + * @see {@link mergeScan} + * @see {@link scan} + * + * @param accumulator The accumulator function called on each source value. + * @param seed The initial accumulation value. + * @return A function that returns an Observable that emits a single value that + * is the result of accumulating the values emitted by the source Observable. + */ +export function reduce(accumulator: (acc: V | A, value: V, index: number) => A, seed?: any): OperatorFunction { + return operate(scanInternals(accumulator, seed, arguments.length >= 2, false, true)); +} -- cgit v1.2.3