JS inheritance. Explained.

inheritance.js

// via http://www.klauskomenda.com/code/javascript-inheritance-by-example/
// create constructor function for base "class"
function Vehicle(hasEngine, hasWheels) {
    this.hasEngine = hasEngine || false;
    this.hasWheels = hasWheels || false;
}

// create constructor function
function Car (make, model, hp) {    
    this.hp = hp;
    this.make = make;
    this.model = model;
}

// setup inheritance
Car.prototype = new Vehicle(true, true);

// extend Car with prototype
Car.prototype.displaySpecs = function () {
    console.log(this.make + ", " + this.model + ", " + this.hp + ", " + this.hasEngine + ", " + this.hasWheels);
}

// New instance of Car
var myAudi = new Car ("Audi", "A4", 150);

// prove inheritance worked
console.log(myAudi.displaySpecs()); // logs: Audi, A4, 150, true, true

// extend Vehicle
Vehicle.prototype.hasTrunk = true;

// show inherited property
console.log(myAudi.hasTrunk); // logs: true


// another from http://www.objectplayground.com/

// Parent class constructor
function Parent() {
  this.a = 42;
}

// Parent class method
Parent.prototype.method = function method() {};

// Child class constructor
function Child() {
  Parent.call(this);
  this.b = 3.14159
}

// Inherit from the parent class
Child.prototype = Object.create(Parent.prototype);
Child.prototype.constructor = Child;

// Child class method
Child.prototype.method = function method() {
  Parent.prototype.method.call(this);
};

// Instantiate
this.instance = new Child();