title: Is it possible to listen if a function was fired in another .js file
body: <p>Is is possible to listen if a function was fired up in another .js file?</p>
  
  <p>For example <code>function foo()</code> was fired.</p>
  
  <p>Is it possible to run a piece of code everytime <code>foo()</code> is run without placing the code I want to run within that function?</p>