Type Alias BoolNot<A>

BoolNot: TypeEq<A, true> extends true
? false
: TypeEq<A, false> extends true ? true : never

Performs a logical NOT operation on a boolean literal type A. This is the type-level equivalent of the JavaScript ! operator.

Type Parameters

A extends boolean
A boolean literal type (true or false).

Returns

The logical negation of A: false if A is true, true if A is false.

Example

type Result1 = BoolNot<true>;  // false
type Result2 = BoolNot<false>; // true

// Useful in conditional types
type IsDisabled<T> = T extends { enabled: infer E }
  ? E extends boolean
    ? BoolNot<E>
    : never
  : true;

type Test1 = IsDisabled<{ enabled: true }>;  // false
type Test2 = IsDisabled<{ enabled: false }>; // true