effect-io-ai

Package: effect
Module: Match

Match.orElseAbsurd

Returns a matcher that throws an error if no pattern matches.

When to use

Use to finalize a matcher when every remaining unmatched case should be impossible.

Details

This function finalizes a matcher by ensuring that if no patterns match, an error is thrown. It is useful when all cases should be covered, and any unexpected input should trigger an error instead of returning a default value.

When used, this function removes the need for an explicit fallback case and ensures that an unmatched value is never silently ignored.

Example (Throwing on unmatched input)

import { Match } from "effect"

const strictMatcher = Match.type<"a" | "b">().pipe(
  Match.when("a", () => "Found A"),
  Match.when("b", () => "Found B"),
  // Will throw if input is neither "a" nor "b"
  Match.orElseAbsurd
)

console.log(strictMatcher("a")) // "Found A"
console.log(strictMatcher("b")) // "Found B"

// This would throw an error at runtime:
// strictMatcher("c" as any) // throws

See

• exhaustive for compile-time exhaustive matcher finalization
• orElse for providing a fallback for unmatched input

Signature

declare const orElseAbsurd: <I, R, RA, A, Pr, Ret>(self: Matcher<I, R, RA, A, Pr, Ret>) => [Pr] extends [never] ? (input: I) => Unify<A> : Unify<A>

Source

Since v4.0.0