jquery - javascript design pattern - callback though a public method -

i'd able use public method callback instead of passing argument

as in

 function car() {      var = this;      this.ongearchanged = function(callback) {         callback();     };      settimeout(that.ongearchanged, 2000); }  var car = new car(); car.ongearchanged(function(){    console.log("gear changed");  }); 

instead of

var ongearchanged = function(){     console.log("gear changed") } var car = new car(arg, arg, ongearchange); 

how go it? should follow observer pattern?

i think need this:

function event(sender) {     this._sender = sender;     this._listeners = []; }  event.prototype = {     attach: function (listener) {         this._listeners.push(listener);     },     notify: function (args) {         (var = 0; < this._listeners.length; i++) {             this._listeners[i](this._sender, args);         }     } }; 

you car class:

function car(gear) {      var self = this;       self.gear = gear;      self.gearchanged = new event(this);       //example method trigger gearchanged event. in real code, may have different logic      self.changegear = function (newgear){          self.gear = newgear;          //notify subscribers          self.gearchanged.notify(newgear);      } } 

example code subscribe events:

var car = new car("gear"); car.gearchanged.attach(function (sender,args){     console.log("gear changed");     console.log("new gear value is:" + args); }); //do logic may trigger gearchanged event. car.changegear("new gear"); 

you can attach more event handlers , these event handlers called. , can add more events like: tirechanged,.. structure.