// export type FilterFlags<Base, Condition> = {
//     [Key in keyof Base]: Base[Key] extends Condition ? Base[Key] : never
// };
// export type AllowedNames<Base, Condition> = keyof FilterFlags<Base, Condition>;
// export type SubType<Base, Condition> = Pick<Base, AllowedNames<Base, Condition>>;

export type FilterFlags<Base, Condition> = {
    [Key in keyof Base]: Base[Key] extends Condition ? Key : never
};
export type AllowedNames<Base, Condition> = FilterFlags<Base, Condition>[keyof Base];
export type SubType<Base, Condition> = Pick<Base, AllowedNames<Base, Condition>>;

export type WithSelf<S, F extends (...a) => any> = (self: S, ...args: Parameters<F>) => ReturnType<F>;
export type FuncOrMethod<T, F extends () => any> = WithSelf<T, F> | AllowedNames<T, F>;

export type ClassOf<T> = Function & { prototype: T }
export type ConstructorOf<T> = { new(...args): T, prototype: T }