OptionalKeys<Type> constructs a union type by picking all optional properties of object type Type
interface StudentWithOptionalName {
homework: string | undefined;
name?: string;
score: number;
}
type PropertiesThatStudentDoesNotUsuallyHave = OptionalKeys<StudentWithOptionalName>;
// ^? 'name'It means we can either set a new value or delete it
declare const user: StudentWithOptionalName;
user.name = "Alex";
delete user.name;TS Playground – https://tsplay.dev/Wo8ePw