Simplest/Cleanest way to implement singleton in JavaScript?

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名媛妹妹
名媛妹妹 2020-11-22 05:17

What is the simplest/cleanest way to implement singleton pattern in JavaScript?

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  •  猫巷女王i
    2020-11-22 05:35

    Here is the simple example to explain singleton pattern in javascript.

     var Singleton=(function(){
          var instance;
          var init=function(){
               return {
                 display:function(){
                 alert("This is a Singleton patern demo");
                  }
                };
               }; 
                return {
                  getInstance:function(){
                       if(!instance){
                         alert("Singleton check");
                          instance=init();
                           }
                   return instance;
                 }
             };
    
        })();
    
       // In this call first display alert("Singleton check")
      // and then alert("This is a Singleton patern demo");
      // It means one object is created
    
        var inst=Singleton.getInstance();
        inst.display();
    
        // In this call only display alert("This is a Singleton patern demo")
       //  it means second time new object is not created, 
       //  it uses the already created object 
    
        var inst1=Singleton.getInstance();
        inst1.display();
    

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