optional | /patterns.ts | fuzzy_octo_guacamole@v2.0.0

function optional

import { optional } from "https://deno.land/x/fuzzy_octo_guacamole@v2.0.0/patterns.ts";

optional<input, p extends unknown extends input ? UnknownPattern : Pattern<input>>(pattern: p): OptionalP<input, p>

P.optional(subpattern) takes a sub pattern and returns a pattern which matches if the key is undefined or if it is defined and the sub pattern matches its value.

Read P.optional documentation on GitHub

Examples

match(value) .with({ greeting: P.optional('Hello') }, () => 'will match { greeting?: "Hello" }')

Type Parameters

input

p extends unknown extends input ? UnknownPattern : Pattern<input>

Parameters

pattern: p

Returns

OptionalP<input, p>