A quick illustration of closures in JavaScript

closures.js

var InnerSchool = (function(){
  function Course(name){
    this.name = name;
  }

  function School(name){
    this.name = name;
    this.courses = [];
  }

  School.prototype.addCourse = function(courseName){
    this.courses.push(new Course(courseName));
  };

  School.prototype.welcome = function(){
    console.log('Welcome to ' + this.name );
  }
  return School;
})();

var fis = new InnerSchool("The Flatiron School");
fis.addCourse("JavaScript");
console.log(fis.courses);