map

map function on IO allows you to change the value in the IO (from type A to B).

Type

// IO<R, E, A>type: map<B>(f: (val: A) => B): IO<R, E, B>

Usage

io[IO<R, E, number>].map((value) => value + 1) // from number to numberio[IO<R, E, number>].map((value) => `Index: ${value}`) // from number to string
io[IO<R, E, string>].map((value) => value.length) // from string to number

Example

import { IO, Runtime, Either } from "ziojs";
const func = (input: number) => Either.Right(input);
const addOne = (val: number) => val + 1;
const io = new IO(func);
Runtime.unsafeRunSync(io.map(addOne).provide(4)) // 5