effect-io-ai

Package: effect
Module: Match

Match.TypeMatcher

Represents a pattern matcher that operates on types rather than specific values.

Details

A TypeMatcher is created when using Match.type<T>() and allows you to define patterns that will be applied to values of the specified type. It maintains type-level information about the input type, applied filters, remaining cases, and expected results.

Example (Creating a type matcher)

import { Match } from "effect"

// Create a TypeMatcher for string | number
const matcher = Match.type<string | number>().pipe(
  Match.when(Match.string, (s) => `String: ${s}`),
  Match.when(Match.number, (n) => `Number: ${n}`),
  Match.exhaustive
)

console.log(matcher("hello")) // "String: hello"
console.log(matcher(42)) // "Number: 42"

Signature

export interface TypeMatcher<in Input, out Filters, out Remaining, out Result, out Return = any> extends Pipeable {
  readonly _tag: "TypeMatcher"
  readonly [TypeId]: {
    readonly _input: T.Contravariant<Input>
    readonly _filters: T.Covariant<Filters>
    readonly _remaining: T.Covariant<Remaining>
    readonly _result: T.Covariant<Result>
    readonly _return: T.Covariant<Return>
  }
  readonly cases: ReadonlyArray<Case>
  add<I, R, RA, A>(_case: Case): TypeMatcher<I, R, RA, A>
}

Source

Since v4.0.0