effect-io-ai

Package: effect
Module: Effect

Effect.retryOrElse

Retries a failing effect and runs a fallback effect if retries are exhausted.

Details

The Effect.retryOrElse function attempts to retry a failing effect multiple times according to a defined Schedule policy.

If the retries are exhausted and the effect still fails, it runs a fallback effect instead.

When to Use

This function is useful when you want to handle failures gracefully by specifying an alternative action after repeated failures.

Example (Retrying with Fallback)

import { Effect, Schedule, Console } from "effect"

let count = 0

// Simulates an effect with possible failures
const task = Effect.async<string, Error>((resume) => {
  if (count <= 2) {
    count++
    console.log("failure")
    resume(Effect.fail(new Error()))
  } else {
    console.log("success")
    resume(Effect.succeed("yay!"))
  }
})

// Retry the task with a delay between retries and a maximum of 2 retries
const policy = Schedule.addDelay(Schedule.recurs(2), () => "100 millis")

// If all retries fail, run the fallback effect
const repeated = Effect.retryOrElse(
  task,
  policy,
  // fallback
  () => Console.log("orElse").pipe(Effect.as("default value"))
)

Effect.runPromise(repeated).then(console.log)
// Output:
// failure
// failure
// failure
// orElse
// default value

See

• retry for a version that does not run a fallback effect.

Signature

declare const retryOrElse: { <A1, E, R1, A2, E2, R2>(policy: Schedule.Schedule<A1, NoInfer<E>, R1>, orElse: (e: NoInfer<E>, out: A1) => Effect<A2, E2, R2>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E2, R1 | R2 | R>; <A, E, R, A1, R1, A2, E2, R2>(self: Effect<A, E, R>, policy: Schedule.Schedule<A1, NoInfer<E>, R1>, orElse: (e: NoInfer<E>, out: A1) => Effect<A2, E2, R2>): Effect<A | A2, E2, R | R1 | R2>; }

Source

Since v2.0.0