Javascript best Singleton pattern

Question

Possible Duplicate    Simplest Cleanest way to implement singleton in JavaScript        I m using this pattern for singletons  in the example the singleton is PlanetEarth   var NAMESPACE   function           var privateFunction1   function              privateFunction2                var privateFunction2   function              alert  I  m private                 var Constructors            Constructors PlanetEarth   function              privateFunction1            privateFunction2                Constructors PlanetEarth prototype             someMethod  function                  if  console  amp  amp  console log                    console log  some method                                                     Constructors Person   function  name  address            this name   name          this address   address              Constructors Person prototype             walk  function                  alert  STOMP                           return           Person  Constructors Person     there can be many         PlanetEarth  new Constructors PlanetEarth      there can only be one                 Since PlanetEarth s constructor remains private  there can only be one   Now  something tells me that this self-cooked thing isn t the best one can do  mostly because I don t have an academic education and I tend to solve problems in stupid ways  What would you propose as a better alternative my method  where better is defined as stylistically better and or more powerful

User · Answer

Why use a constructor and prototyping for a single object?

The above is equivalent to:

var earth= {
    someMethod: function () {
        if (console && console.log)
            console.log('some method');                             
    }
};
privateFunction1();
privateFunction2();

return {
    Person: Constructors.Person,
    PlanetEarth: earth
};

User · Answer

1  UPDATE 2019  ES7 Version  class Singleton       static instance       constructor             if  instance                return instance                     this instance   this             foo                             console log new Singleton       new Singleton        2  ES6 Version  class Singleton       constructor             const instance   this constructor instance          if  instance                return instance                     this constructor instance   this             foo                             console log new Singleton       new Singleton         Best solution found  http   code google com p jslibs wiki JavascriptTips Singleton pattern  function MySingletonClass         if  arguments callee  singletonInstance        return arguments callee  singletonInstance         arguments callee  singletonInstance   this     this Foo   function                         var a   new MySingletonClass    var b   MySingletonClass    console log  a     b       prints  true   For those who want the strict version    function  global       use strict     var MySingletonClass   function           if  MySingletonClass prototype  singletonInstance          return MySingletonClass prototype  singletonInstance             MySingletonClass prototype  singletonInstance   this       this Foo   function                               var a   new MySingletonClass    var b   MySingletonClass    global result   a     b      window     console log result

User · Answer

function SingletonClass             demo variable     var names               instance of the singleton     this singletonInstance   null          Get the instance of the SingletonClass        If there is no instance in this singletonInstance  instanciate one     var getInstance   function             if   this singletonInstance                   create a instance             this singletonInstance   createInstance                          return the instance of the singletonClass         return this singletonInstance                function for the creation of the SingletonClass class     var createInstance   function                 public methodes         return               add   function name                    names push name                              names   function                     return names                                        wen constructed the getInstance is automaticly called and return the SingletonClass instance      return getInstance       var obj1   new SingletonClass    obj1 add  Jim    console log obj1 names        prints    Jim    var obj2   new SingletonClass    obj2 add  Ralph    console log obj1 names        Ralph is added to the singleton instance and there for also acceseble by obj1    prints    Jim    Ralph   console log obj2 names        prints    Jim    Ralph    obj1 add  Bart    console log obj2 names        prints    Jim    Ralph    Bart

User · Answer

Extending the above post by Tom  if you need a class type declaration and access the singleton instance using a variable  the code below might be of help  I like this notation as the code is little self guiding   function SingletonClass        if   arguments callee instance           return arguments callee instance      arguments callee instance   this      SingletonClass getInstance   function         var singletonClass   new SingletonClass        return singletonClass       To access the singleton  you would  var singleTon   SingletonClass getInstance

[javascript] Javascript: best Singleton pattern

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