Execute Jquery Every Time A Specific Function Runs

Is it possible to execute something every time a specific function runs without any knowledge about that function besides its name? This would be similar to bind var clicked = 0; $

Solution 1:

Try something like this:

var temp = my_function, fired = 0;
my_function = function() {
    fired++;
    temp.apply(this,arguments);
}

Solution 2:

I think something like this may be the closest you can come:

functionadjustFunctionToCount(f){
    var count = 0;
    functionnewF(){
        count++;
        f.apply(this, arguments);
    }
    newF.getCount = function(){ return count; };
    return newF;
}

And so if you have

functionhandler(val){
    console.log('called with val ' + val);
}

You could do

handler = adjustFunctionToCount(handler);
handler('a');
handler('b');
console.log(handler.getCount());

FIDDLE

And needless to say you could create your function inline

var handler = adjustFunctionToCount(function(val){ console.log('called with val ' + val); });

handler('a');
handler('b');
console.log(handler.getCount());

UPDATED FIDDLE

Solution 3:

I'm pretty sure that's impossible in the general case.

Remember, functions are objects, really, and the name of a function is just a variable. Functions can exist without being assigned to a named variable, the variables can be out of your scope, or reassigned/swapped around. In any case, I know of no API that lets you hook onto a JS function call.

This may be of interest: Can I intercept a function called directly?

Solution 4:

This is where event driven programming comes in - and jQuery makes it really easy to do.

var myFunction = function() {
 //...//...//...
 $(document).trigger('someEvent');

}


$(document).on('someEvent',function() {
 //the function you would like to run every time myFunction is called
});

Solution 5:

Try this:

var count = (function(){
  var c = 0;
  returnfunction(){
    alert(c++);
  };
})();
$('#foo').click(count);

OR

$('#foo').bind('click', count);

When an Anonymous Function or a Variable that represents a Function is passed it is the same thing. You could make your own code that executes a Function like this:

function executeFun(func){
  return func();
}
executeFun(count)
executeFun(function(){
  /*everything happens in here. The Anonymous Function will be called
    automatically because of the parameter next to the variable func above */
})

Although, that example is impractical it shows you what happens internally. Also, I solved your potential global scope variable problem with a Closure. For more on Closures visit https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Closures .