Package: effect
Module: Iterable
Creates an iterable by applying a function to consecutive integers.
Details
The function is called with each index starting from 0. If no length is
specified, the iterable is infinite. This is useful for generating
sequences, patterns, or any indexed data.
Example (Generating values by index)
import { Iterable } from "effect"
// Generate first 5 even numbers
const evens = Iterable.makeBy((n) => n * 2, { length: 5 })
console.log(Array.from(evens)) // [0, 2, 4, 6, 8]
// Generate squares
const squares = Iterable.makeBy((n) => n * n, { length: 4 })
console.log(Array.from(squares)) // [0, 1, 4, 9]
// Infinite sequence (be careful when consuming!)
const naturals = Iterable.makeBy((n) => n)
const first10 = Iterable.take(naturals, 10)
console.log(Array.from(first10)) // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Signature
declare const makeBy: <A>(f: (i: number) => A, options?: { readonly length?: number; }) => Iterable<A>
Since v2.0.0