effect-io-ai

Package: effect
Module: Effect

Effect.promise

Creates an Effect that represents an asynchronous computation guaranteed to succeed.

Details

The provided function (thunk) returns a Promise that should never reject; if it does, the error will be treated as a “defect”.

This defect is not a standard error but indicates a flaw in the logic that was expected to be error-free. You can think of it similar to an unexpected crash in the program, which can be further managed or logged using tools like catchAllDefect.

Interruptions

An optional AbortSignal can be provided to allow for interruption of the wrapped Promise API.

When to Use

Use this function when you are sure the operation will not reject.

Example (Delayed Message)

import { Effect } from "effect"

const delay = (message: string) =>
  Effect.promise<string>(
    () =>
      new Promise((resolve) => {
        setTimeout(() => {
          resolve(message)
        }, 2000)
      })
  )

//      ┌─── Effect<string, never, never>
//      ▼
const program = delay("Async operation completed successfully!")

See

• tryPromise for a version that can handle failures.

Signature

declare const promise: <A>(evaluate: (signal: AbortSignal) => PromiseLike<A>) => Effect<A>

Source

Since v2.0.0