effect-io-ai

Package: effect
Module: Array

Array.scan

Folds left-to-right while keeping every intermediate accumulator value.

When to use

Use to compute a running accumulator where each intermediate value is needed.

Details

The output length is input.length + 1 because it starts with the initial value. The result is always a NonEmptyArray. Use reduce if you only need the final accumulated value.

Example (Running totals)

import { Array } from "effect"

const result = Array.scan([1, 2, 3, 4], 0, (acc, value) => acc + value)
console.log(result) // [0, 1, 3, 6, 10]

See

• scanRight — right-to-left scan
• reduce — fold without intermediate values

Signature

declare const scan: { <B, A>(b: B, f: (b: B, a: A) => B): (self: Iterable<A>) => NonEmptyArray<B>; <A, B>(self: Iterable<A>, b: B, f: (b: B, a: A) => B): NonEmptyArray<B>; }

Source

Since v2.0.0