Why and how to use IIFE in javascript

Question

In this example code:

    (function(){
           var obj = function() {

           };

           obj.prototype.hello = function(){
                 consol         


        

Answer 1

To avoid polluting outer scope. You're sure no variables are going to "get out" of it. But yes, you do need to export it. Either using window.obj = obj; from inside (to make it global) or return it :

var obj = (function() {
  var obj = function() {};
  obj.prototype.sayHello = function() {}; 
  return obj;
})();