effect-io-ai

Package: effect
Module: Effect

Effect.map

Transforms the value inside an effect by applying a function to it.

Syntax

const mappedEffect = pipe(myEffect, Effect.map(transformation))
// or
const mappedEffect = Effect.map(myEffect, transformation)
// or
const mappedEffect = myEffect.pipe(Effect.map(transformation))

Details

map takes a function and applies it to the value contained within an effect, creating a new effect with the transformed value.

It’s important to note that effects are immutable, meaning that the original effect is not modified. Instead, a new effect is returned with the updated value.

Example (Adding a Service Charge)

import { pipe, Effect } from "effect"

const addServiceCharge = (amount: number) => amount + 1

const fetchTransactionAmount = Effect.promise(() => Promise.resolve(100))

const finalAmount = pipe(
  fetchTransactionAmount,
  Effect.map(addServiceCharge)
)

Effect.runPromise(finalAmount).then(console.log)
// Output: 101

See

• mapError for a version that operates on the error channel.
• mapBoth for a version that operates on both channels.
• flatMap or andThen for a version that can return a new effect.

Signature

declare const map: { <A, B>(f: (a: A) => B): <E, R>(self: Effect<A, E, R>) => Effect<B, E, R>; <A, E, R, B>(self: Effect<A, E, R>, f: (a: A) => B): Effect<B, E, R>; }

Source

Since v2.0.0