effect-io-ai

Package: effect
Module: Effect

Effect.catchSome

Catches and recovers from specific types of errors, allowing you to attempt recovery only for certain errors.

Details

catchSome lets you selectively catch and handle errors of certain types by providing a recovery effect for specific errors. If the error matches a condition, recovery is attempted; if not, it doesn’t affect the program. This function doesn’t alter the error type, meaning the error type remains the same as in the original effect.

Example (Handling Specific Errors with Effect.catchSome)

import { Effect, Random, Option } from "effect"

class HttpError {
  readonly _tag = "HttpError"
}

class ValidationError {
  readonly _tag = "ValidationError"
}

//      ┌─── Effect<string, HttpError | ValidationError, never>
//      ▼
const program = Effect.gen(function* () {
  const n1 = yield* Random.next
  const n2 = yield* Random.next
  if (n1 < 0.5) {
    yield* Effect.fail(new HttpError())
  }
  if (n2 < 0.5) {
    yield* Effect.fail(new ValidationError())
  }
  return "some result"
})

//      ┌─── Effect<string, HttpError | ValidationError, never>
//      ▼
const recovered = program.pipe(
  Effect.catchSome((error) => {
    // Only handle HttpError errors
    if (error._tag === "HttpError") {
      return Option.some(Effect.succeed("Recovering from HttpError"))
    } else {
      return Option.none()
    }
  })
)

See

• catchIf for a version that allows you to recover from errors based on a predicate.

Signature

declare const catchSome: { <E, A2, E2, R2>(pf: (e: NoInfer<E>) => Option.Option<Effect<A2, E2, R2>>): <A, R>(self: Effect<A, E, R>) => Effect<A2 | A, E | E2, R2 | R>; <A, E, R, A2, E2, R2>(self: Effect<A, E, R>, pf: (e: NoInfer<E>) => Option.Option<Effect<A2, E2, R2>>): Effect<A | A2, E | E2, R | R2>; }

Source

Since v2.0.0