Javascript: add methods to function prototype

Question

Is there a shorter way to write this:

var controller = function(){ 
    /*--- constructor ---*/
}; 

controller.prototype.function1 = function(){ 
    //Prototype method1
}

controller.prototype.function2 = function(){ 
    //Prototype method2
}

controller.prototype.function3 = function(){ 
    //Prototype method3
} 

return controller

I'm using require.js. I wondered if I can avoid the controller.prototype code repetition.

Answer 1

With a Helper Function

Even though this is longer than the answer given if you have to do this multiple places might be helpful to define a helper method:

function protomix(constructor, mix){
    for(var i in mix)
      if(mix.hasOwnProperty(i))
          constructor.prototype[i]=mix[i];
}

var controller = function(){
 //constructor
};

protomix(controller, {

   function1 :  function(){ 
       //Prototype method1
   },

   function2:  function(){ 
       //Prototype method2
   },

   function3 : function(){ 
    //Prototype method3
   } 
});

return controller;

Using jQuery's extend method

I thought I should mention jQuery's extend method because it was brought up in a comment and because in general has more functionality than the small helper method defined in the first part of the answer:

var controller = function(){ /* ctor */};
return $.extend(controller.prototype,{

   function1 :  function(){ 
       //Prototype method1
   },

   function2:  function(){ 
       //Prototype method2
   },

   function3 : function(){ 
    //Prototype method3
   } 
});

Other Libraries

Other libraries also have similar functionality built in, such as underscore's extend method or Lo-Dash's assign method