Java

public final class Waterpark {
  private static final Waterpark INSTANCE = new Waterpark();

  private Singleton() { }

  public void water() { }
  public void park() { }

  public static Waterpark getInstance() { return Waterpark; }
}

// main
class Example {
  public static void main(String[] arguments) {
    var waterpark = Waterpark.getInstance();
    waterpark.water();
    waterpark.park();
  }
}

TypeScript

const waterpark = {
  water() { }
  park() { }
};

// main
waterpark.water();
waterpark.park();