Question

How can i overload the calling process of any function?

In my web app i want to do something before the call of a function and something after it how can i do this without prototyping the call method ( because i tried this and it will work only if i call a function as myFunction.call() ) and still have the requested effect.

I have tried everything for making it work, but nothing works, and to do it the hard way ( by call method ) it’s non-practicable because i would have to rewrite all my code.

Could someone help please?

Answer 1

You can change each function definition manually.
You can change each function call manually.
If either of these refactorings is out of the scope of your problems then you’re in a spot of bother.

There is no generic way that I’m familiar with to solve your problem.

However if your functions are globally accessible or namespaced then you can do the following quite easily (and can make it much more generic by parametrising the pre and post functions etc.):

NS = {
   foo : function(){ console.log('foo'); },
   bar : function(){ console.log('bar'); }
};

// <-- new code goes here

NS.foo();
NS.bar();

// new code below, that should go after definitions but before the calls

(function(){

   var pre = function(){ console.log('pre'); },
       post = function(){ console.log('post'); };

   for (var fn in NS) {
      NS[fn] = (function(fn){ return function(){ pre(); fn(); post(); }; })(fn);
   }

})();