passing extra parameter to event handler

Question

In the code below i have util.doSomething() method which takes json object as parameter. When util is done doing something it calls onDone event handler by passing a response as parameter.

I wanted to know in the code below if it is possible to pass id to update event handler?

$(function(){
  $('#btn').click(function(){

    var id = $(this).attr('id');

    util.doSomething({
          property1: "SomeValue1",
          property2: "SomeValue2",
          onDone: update //ho do i pass id to update event handler?
      })
  })

   function update(response,id)
   {
      //update
   }
})

I know i can get hold of id using inline event handler. like

  $("#btn").click(function(){
   var id = $(this).attr('id');

    util.doSomething({
          property1: "SomeValue1",
          property2: "SomeValue2",
          onDone: function(response){
               // now i can use id here
         }
      })
  })

Answer 1

Instead of setting onDone to update , you can set it to a function that calls update with the arguments you want.

util.doSomething({
    property1: "SomeValue1",
    property2: "SomeValue2",
    onDone: function(response) {
      return update(response, id);
    }
})

Answer 2

You can use the .bind method and the arguments object inside the function to access extra parameters you want to pass in

$(function(){
  $('#btn').click(function(){

    var id = $(this).attr('id');

    util.doSomething({
          property1: "SomeValue1",
          property2: "SomeValue2",
          onDone: update.bind(this, id)
      })
  })

   function update()
   {
       console.log(arguments); // inside arguments you should see all your parameters
       // arguments[0] your id
       // arguments[1] your response
   }
})