Javascript "Singleton"

singleton_test.js

/**
 * let c = new MyClass();
 * c.foo();
 * let d = new MyClass();
 * d.foo();
 */
(() => {
  let instance;
  // global 
  window.MyClass = function(){  
  	if(instance){
    	return instance;
    }
    /** "class" scope implementation */
    let count = 1;
    
    this.foo = function(){
      $('body').append($('<div/>').text('Singleton Test - Count: '+count)); // jquery append
      count++;
    }
    
    /** end scope */
    
    /** instance */
    instance = this;
  };
})();