Singleton Pattern in JavaScript

In software engineering, the singleton pattern is a design pattern that restricts the instantiation of a class to one object. This is useful when exactly one object is needed to coordinate actions across the system.

In JavaScript this pattern restricts instantiation of an object to a single reference thus reducing its memory footprint and allowing a "delayed" initialization on an as-needed basis. This isn't too common among JavaScript projects.

Here is how a singleton pattern can be implemented with JavaScript

1. Easiest way is using object literals
   

   
   var singletonObject ={
       method1:function(){
           
       },
       method2:function(){
       
       }
   }

   
   
2. Little more organized way using closures
   

   
   var singletonObject = (function(){
       var instance;
       
       function initiateInstance(){
           var object = new Object("my Object");
           return object;
       }
       
       return{
           getSingletonInstance:function(){
               if(!instance){
                   instance=initiateInstance();
               }
               return instance;
           }
       }
       
   })();
   
   

   when we access the object it can be done like,

   
   var instance1=singletonObject.getSingletonInstance();
   var instance2=singletonObject.getSingletonInstance();
   
   //instance1===instance2