Exclude<UnionType, ExcludedMembers>

[nmsn]

Constructs a type by excluding from UnionType all union members that are assignable to ExcludedMembers.

type T0 = Exclude<"a" | "b" | "c", "a">;
type T0 = "b" | "c"

type T1 = Exclude<"a" | "b" | "c", "a" | "b">;
type T1 = "c"

type T2 = Exclude<string | number | (() => void), Function>;

[nmsn]

/**
 * Exclude from T those types that are assignable to U
 */
type Exclude<T, U> = T extends U ? never : T;