javascript singleton

singleton.js

function singleton() {
  var instance = (function() {
    var privateVar;

    function privateMethod () {
      // ...
    }

    return { // public interface
      publicMethod1: function () {
          // private members can be accessed here
       },
      publicMethod2: function () {
        // ...
      }
    };
  })();

  singleton = function () { // re-define the function for subsequent calls
    return instance;
  };

  return singleton(); // call the new function
}