Square extends Rectangle - Javascript Object

Javascript examples for Object:prototype

  1. HOME
  2. Javascript
  3. Object
  4. prototype

Description

Square extends Rectangle

Demo Code


function Rectangle(length, width) {
  this.length = length;/*from  w w  w .j a  v a 2s.c  o m*/
  this.width = width;
}

Rectangle.prototype.getArea = function() {
  return this.length * this.width;
};

Rectangle.prototype.toString = function() {
  return "[Rectangle " + this.length + "x" + this.width + "]";
};

// inherits from Rectangle
function Square(size) {
  Rectangle.call(this, size, size);
}

Square.prototype = Object.create(Rectangle.prototype, {
  constructor: {
    configurable: true,
    enumerable: true,
    value: Square,
    writable: true
  }
});

// call the supertype method
Square.prototype.toString = function() {
  var text = Rectangle.prototype.toString.call(this);
  return text.replace("Rectangle" , "Square");
};

var rect = new Rectangle(5, 10);
var square = new Square(6);

console.log(rect.getArea());
console.log(square.getArea());

console.log(rect.toString());
console.log(square.toString());

console.log(rect instanceof Rectangle);
console.log(rect instanceof Object);

console.log(square instanceof Square);
console.log(square instanceof Rectangle);
console.log(square instanceof Object);

Related Tutorials