Design Pattern - Singletone

design-pattern-singletone.js

var TaskManager = (function(){

var taskManager = null;
  function createInstance(id) {
    if(taskManager === null) {
      taskManager = new Object();
      taskManager.id = id;
      return taskManager;
    }
    return taskManager;
  }

  return {
    getInstance: createInstance
  }
})();

var taskManager1 = TaskManager.getInstance(1);
var taskManager2 = TaskManager.getInstance(2);

console.log(taskManager1.id);   // 1
console.log(taskManager2.id);   // 1

console.log(taskManager1 === taskManager2);   // true