when | /patterns.ts | fuzzy_octo_guacamole@v5.0.1

function when

import { when } from "https://deno.land/x/fuzzy_octo_guacamole@v5.0.1/patterns.ts";

when<input, p extends (value: input) => unknown>(predicate: p): GuardP<input, p extends (value: any) => value is infer narrowed ? narrowed : never>

P.when((value) => boolean) returns a pattern which matches if the predicate returns true for the current input.

when<input, narrowed extends input, excluded>(predicate: (input: input) => input is narrowed): GuardExcludeP<input, narrowed, excluded>

P.when((value) => boolean) returns a pattern which matches if the predicate returns true for the current input.

Examples

match<{ age: number }>(value) .with({ age: P.when(age => age > 21) }, (x) => 'will match if value.age > 21' )

input

p extends (value: input) => unknown

predicate: p

GuardP<input, p extends (value: any) => value is infer narrowed ? narrowed : never>

input

narrowed extends input

excluded

predicate: (input: input) => input is narrowed