adding back ExtendsType

Author: cblanquera

src/types.ts

@@ -9,6 +9,15 @@ import type Request from './router/Request.js';
 import type Response from './router/Response.js';
 import type Router from './router/Router.js';
 
+//--------------------------------------------------------------------//
+// General Types
+
+export type ExtendsType<T, U> = U & Pick<T, Exclude<keyof T, keyof U>>;
+
+export type Constructor<T, U extends Record<string, unknown> = {}> = U & {
+  new (): T; 
+};
+
 //--------------------------------------------------------------------//
 // Data Types