Question

I have the following functions that is called every 2 seconds to load some data. It registers the function [do] to do the stuff with the response. (the example is simplified).

function doRequest (){
    $.ajax({ url: 'www.google.com.pe', success: function (response) {do(response)} });
}

function do (text){
    var i = setInterval(doRequest, 2000);
}

I wonder if there is any way that I can create a function that is called every time the [do] function is called with out needing to add a call to the listener inside the do function. If there is any better way to do it with jQuery, like a plugin I’d appreciate the help.

[Edit] The idea is not whether it works or not. My question was about if I can add a custom listener to the "do" function which was already implemented. Something like addActionListener("do", "after", doSomeThingElse),sSo I could do some thing else just after the do function has finished.

Answer 1

If you want to keep existing code as it is, you could wrap do() in another function which in turn calls do() and your new function (say do_this_as_well()).

See the example below (I renamed do() to do_this() to avoid confusion around the reserved keyword do). This works because global functions are nothing but variables with function objects in them. These variables can be overwritten, in this case with a new function that calls the old one:

function do_this(response) { ... }

(function()
{
    var previous=do_this;
    do_this=function(response) { previous(response); do_this_as_well(); }
})();