type Constructor<T = {}> = new (...args: any[]) => T;
function Watch<TBase extends Constructor>(Base: TBase) {
  return class extends Base {
    change$: Subject<any>;
    constructor(...args: any[]) {
      super(...args);
      this.change$ = new Subject<this>();
      return new Proxy(this, {
        set: function(obj: any, prop:any , value:any) {
          obj[prop] = value;
          obj.change$.next({
            obj,
            prop,
            value
          });
          return true;
        }
      })
    }
  };
}