Magic catch-all method in Typescript class by extending Javascript Proxy class to build the perfect Value Object base class

value-object-proxied-base-class.ts

type Setters<Type> = {
  [Property in keyof Type as `set${Capitalize<string & Property>}`]: (newValue: Type[Property]) => Type & Setters<Type>
};

abstract class VO<T> {
  constructor(
    public readonly type: any,
    public readonly excludedProperties: string[],
  ) {
    return (new Proxy(this, {
      apply: (target, thisArg, argArray) => {
        if (!thisArg.hasOwnProperty(target)) {
          throw new Error(`Method ${target} is not defined on ${thisArg}`);
        }

        return thisArg[target](...argArray);
      }
    }) as unknown as VO<T> & Setters<T>);
  }
}

class InviteeVO extends VO<InviteeVO> {
  constructor(
    public readonly name: string,
    public readonly email: string,
    public readonly invite: number,

  ) {
    super(Invitee, ['name', 'status', 'invite']);

    return (this as unknown as InviteeVO & Setters<InviteeVO>);
  }
}

type InviteeSetters = Setters<InviteeVO>;
export const Invitee: typeof InviteeVO & InviteeSetters = InviteeVO as any;

const john = new InviteeVO('John Snow', '[email protected]', 1) as InviteeVO & InviteeSetters;
const arya = john.setName('Arya Stark').setInvite(2);