class Base {
  static count = 0;
  static #secret = 42;
  static {
    Base.count = 10;
  }
  static getSecret() {
    return this.#secret;
  }
}

class Derived extends Base {
  static count = Base.count + 5;
}

let result;
try {
  result = Derived.getSecret();
} catch (e) {
  result = e.constructor.name;
}

console.log(Base.count, Derived.count, result);