const Loggable = {
  log() { return `[${this.constructor.name}] ${this.toString()}`; }
};

class Base {
  toString() { return 'Base instance'; }
}

Object.setPrototypeOf(Base.prototype, Loggable);

class Derived extends Base {
  toString() { return 'Derived instance'; }
}

const b = new Base();
const d = new Derived();

console.log(b.log(), d.log(), Object.getPrototypeOf(Derived.prototype) === Base.prototype);