Type Alias StrictExclude<T, U>

StrictExclude: T extends U ? never : T

Excludes from union type T those types that are assignable to U. This is a stricter version that requires U to extend T.

Type Parameters

T
The union type to exclude from.
U extends T
The type to exclude, must extend T.

Returns

The union T minus U.

Example

type Union = 'a' | 'b' | 'c';
type Remaining = StrictExclude<Union, 'a' | 'b'>; // 'c'
// type Invalid = StrictExclude<Union, 'a' | 'd'>; // Error: 'd' is not assignable to Union