effect-io-ai

Package: effect
Module: Effect

Effect.matchEager

Handles both success and failure cases of an effect without performing side effects, with eager evaluation for resolved effects.

When to use

Use when you need to handle both success and failure cases of an already-resolved Effect with optimized handling.

Details

matchEager works like match but provides better performance for resolved effects (Success or Failure). When the effect is already resolved, it applies the handlers immediately without fiber scheduling. For unresolved effects, it falls back to the regular match behavior.

Example (Pattern matching eagerly when possible)

import { Effect } from "effect"

const program = Effect.gen(function*() {
  const result = yield* Effect.matchEager(Effect.succeed(42), {
    onFailure: (error) => `Failed: ${error}`,
    onSuccess: (value) => `Success: ${value}`
  })
  console.log(result) // "Success: 42"
})

See

• match for the non-eager version.
• matchEffect if you need to perform side effects in the handlers.

Signature

declare const matchEager: { <E, A2, A, A3>(options: { readonly onFailure: (error: E) => A2; readonly onSuccess: (value: A) => A3; }): <R>(self: Effect<A, E, R>) => Effect<A2 | A3, never, R>; <A, E, R, A2, A3>(self: Effect<A, E, R>, options: { readonly onFailure: (error: E) => A2; readonly onSuccess: (value: A) => A3; }): Effect<A2 | A3, never, R>; }

Source

Since v4.0.0