effect-io-ai

Package: effect
Module: Tuple

Tuple.mapPick

Applies a Struct.Lambda transformation only to the elements at the specified indices; all other elements are copied unchanged.

When to use

Use when you want to apply the same transformation to a subset of positions.

Example (Wrapping only selected elements in arrays)

import { pipe, Struct, Tuple } from "effect"

interface AsArray extends Struct.Lambda {
  <A>(self: A): Array<A>
  readonly "~lambda.out": Array<this["~lambda.in"]>
}

const asArray = Struct.lambda<AsArray>((a) => [a])
const result = pipe(
  Tuple.make(1, "hello", true),
  Tuple.mapPick([0, 2], asArray)
)
console.log(result) // [[1], "hello", [true]]

See

• map – apply a lambda to all elements
• mapOmit – apply a lambda to all elements except selected ones

Signature

declare const mapPick: { <const T extends ReadonlyArray<unknown>, const I extends ReadonlyArray<Indices<T>>, L extends Lambda>(indices: I, lambda: L): (self: T) => { [K in keyof T]: K extends `${I[number]}` ? Apply<L, T[K]> : T[K]; }; <const T extends ReadonlyArray<unknown>, const I extends ReadonlyArray<Indices<T>>, L extends Lambda>(self: T, indices: I, lambda: L): { [K in keyof T]: K extends `${I[number]}` ? Apply<L, T[K]> : T[K]; }; }

Source

Since v4.0.0