constructor and supper code example

Example 1: super in javascirpt

class Rectangle {
  constructor(height, width) {
    this.name = 'Rectangle';
    this.height = height;
    this.width = width;
  }
  sayName() {
    console.log('Hi, I am a ', this.name + '.');
  }
  get area() {
    return this.height * this.width;
  }
  set area(value) {
    this._area = value;
  }
}

class Square extends Rectangle {
  constructor(length) {
    this.height; // ReferenceError, super needs to be called first!

    // Here, it calls the parent class's constructor with lengths
    // provided for the Rectangle's width and height
    super(length, length);

    // Note: In derived classes, super() must be called before you
    // can use 'this'. Leaving this out will cause a reference error.
    this.name = 'Square';
  }
}

Example 2: how to do two constructors with super

public Person(String name){
    this(name, 18, "Atlanta");
}

public Person(String name, int age){
    this(name, age, "Atlanta");
}

public Person(String name, int age, String homeTown){
    this.name = name;
    this.age = age;
    this.homeTown = homeTown;   
}