Singleton Pattern: Restricts the instantiation of a class to a single object. It ensures that only one instance of a class is created and provides a global access point to that instance. 


var Singleton = (function() {
  var instance;

  function createInstance() {
    var object = new Object("I am the instance");
    return object;
  }

  return {
    getInstance: function() {
      if (!instance) {
        instance = createInstance();
      }
      return instance;
    }
  };
})();

var instance1 = Singleton.getInstance();
var instance2 = Singleton.getInstance();

console.log(instance1 === instance2); // Output: true