To hide parts of JavaScript my best recommendation is to just not send the undesirable JavaScript to the browser in the first place. There are performance and security improvements to that which would be lost when trying to remove this same code after it does arrive to the browser.

That modification could be as simple as opening the concerned code file in your back end application as a large string and slicing out the parts you don't want. This will likely require some refactoring of the JavaScript code first to ensure the parts you wish to remove are islands whose absence won't break other things.