TypeIncludes

Since v1.3.0

Type-level includes check for tuples. Returns true if any element in the tuple extends the predicate type, otherwise returns false.

Signature

export type TypeIncludes<T extends unknown[], P> = T extends [infer First, ...infer Rest]
	? First extends P
		? true
		: TypeIncludes<Rest, P>
	: false

Parameters

Parameter	Description
T	The tuple type to check
P	The predicate type to look for

Examples

Basic Usage

import type { TypeIncludes } from 'uni-types'

type HasNumber = TypeIncludes<['a', 1, 'b'], number> // true
type HasBoolean = TypeIncludes<['a', 1, 'b'], boolean> // false

Check for Type Existence

import type { TypeIncludes } from 'uni-types'

type Mixed = [string, number, boolean, string, number]
type IncludesString = TypeIncludes<Mixed, number> // true
type IncludesNull = TypeIncludes<Mixed, null> // false