IsUnknown

Resolves to true when a type is unknown, and false otherwise.

type Result = IsUnknown<T>;

Usage

IsUnknown<T>

Use it when a type-level helper should treat an unknown input differently from a concrete type. A plain unknown extends T check is also true for any, but IsUnknown tells the two apart.

import type { IsUnknown } from 'es-toolkit/types';

type A = IsUnknown<unknown>; // true
type B = IsUnknown<any>; // false
type C = IsUnknown<never>; // false
type D = IsUnknown<string>; // false

Type Parameters

• T: The type to check.