effect-io-ai

Package: effect
Module: Effect

Effect.fork

Creates a new fiber to run an effect concurrently.

Details

This function takes an effect and forks it into a separate fiber, allowing it to run concurrently without blocking the original effect. The new fiber starts execution immediately after being created, and the fiber object is returned immediately without waiting for the effect to begin. This is useful when you want to run tasks concurrently while continuing other tasks in the parent fiber.

The forked fiber is attached to the parent fiber’s scope. This means that when the parent fiber terminates, the child fiber will also be terminated automatically. This feature, known as “auto supervision,” ensures that no fibers are left running unintentionally. If you prefer not to have this auto supervision behavior, you can use forkDaemon or forkIn.

When to Use

Use this function when you need to run an effect concurrently without blocking the current execution flow. For example, you might use it to launch background tasks or concurrent computations. However, working with fibers can be complex, so before using this function directly, you might want to explore higher-level functions like raceWith, zip, or others that can manage concurrency for you.

Example

import { Effect } from "effect"

const fib = (n: number): Effect.Effect<number> =>
  n < 2
    ? Effect.succeed(n)
    : Effect.zipWith(fib(n - 1), fib(n - 2), (a, b) => a + b)

//      ┌─── Effect<RuntimeFiber<number, never>, never, never>
//      ▼
const fib10Fiber = Effect.fork(fib(10))

See

• forkWithErrorHandler for a version that allows you to handle errors.

Signature

declare const fork: <A, E, R>(self: Effect<A, E, R>) => Effect<Fiber.RuntimeFiber<A, E>, never, R>

Source

Since v2.0.0