zgangx

//class emulation adding inheritance
var Class = function(parent){
  
  var klass = function(){
    this.init.apply(this, arguments);
  };
   // Change klass' prototype
  //If a parent is passed to the Class constructor
  //we make sure any subclasses share the same prototype.
  //creating a temporary anonymous function prevents instances

zgangx

//this context change by using apply
var proxy = function(func, thisObject){
  return(function(){
  return func.apply(thisObject, arguments);
  });
};
var clicky = {
  name: 'my name is proxy',
  wasClicked: function(){
    console.log(this.name)

zgangx

//Javascript Class inheritance using prototype
//To subclass a class and inherit its properties
//you need to first define a constructor function. 
//Then, you need to assign a new instance of the parent class 
//as the prototype for your constructor function

var Animal = function(){};

Animal.prototype.breath = function(){
  console.log('breath');

zgangx

//if you call contructor function without new prefix.
//function return undefined and create a global variable name
//window.name = 'bob'
// new prefix is creae a new empty context and switches from global
// to current instance.

//By default, if you don’t return anything from a constructor function
//this—the current context—will be returned. 
//Otherwise, you can return any nonprimitive type. 
//For example, we could return a function that would set up a new class

zgangx

$ cd ~
$ sudo curl -sS https://getcomposer.org/installer | sudo php
$ sudo mv composer.phar /usr/local/bin/composer
$ sudo ln -s /usr/local/bin/composer /usr/bin/composer

then you can run 
$ sudo composer install