runningReduce

function

function runningReduce<T, O>(array: readonly T[], reducer: (accumulator: O, current: T, currentIndex: number) => O, initialValue: O): O[]

Calls the given reducer on each element of the given collection, passing its result as the accumulator to the next respective call, starting with the given initialValue. Returns all intermediate accumulator results.

array: readonly T[]

The array to reduce.

reducer: (accumulator: O, current: T, currentIndex: number) => O

The reducer function to apply to each element.

initialValue: O

The initial value of the accumulator.

Returns

An array of all intermediate accumulator results.

import { runningReduce } from "@ende/collections/running-reduce";
import { assertEquals } from "@ende/assert";

const numbers = [1, 2, 3, 4, 5];
const sumSteps = runningReduce(numbers, (sum, current) => sum + current, 0);

assertEquals(sumSteps, [1, 3, 6, 10, 15]);