JQuery do something with class change

My goal is to write an event that will fire if a given element receives a class or when this class is removed.

Let's say I have:

<button id="my_butt_show">showtime</button>
<button id="my_butt_hide">hide me</button>
<span id="the_changer"></span>
<span id="the_end">some text</span>

<script>
  // this is the part of code I can't edit!
    $('#my_butt_show').click( function() {
        $('the_changer').addClass('hiMom');
    });
    $('#my_butt_hide').click( function() {
        $('the_changer').removeClass('hiMom');
    });
</script>

      

        
        
        
      

    

Now I would like something like this:

<script>
   $("#the_changer").onClassAdd('hiMom', $("#the_end").display('true') );
   $("#the_changer").onClassRemove('hiMom', $("#the_end").display('false') );
</script>

      

        
        
        
      

    

Could jQuery (or js itself?) Have something like this?

Note. Of course this is just an example, the real thing I am dealing with is more complicated and although I could have used a simpler solution here, it didn't work for my main task.

thanks for the answers.

---- ---- edit

After the first answers: I don't have access to the piece of code where ".click" or "addClass" is, so I can't just do my stuff there.