It's not possible and it'll never be possible because extensions are essentially client-side JavaScript files which can be trivially accessed in the user profile folder, and inside the browser itself using devtools for any extension page including the popup and the background page.

nturup@ Thanks for the issue.

From the above description, this looks like a feature request to restrict/hide source code of extension.
Hence marking this as Untriaged for further updates from Dev.

Thanks..

Agreed with comment #1, client side JS is by design like this and this should be WAI. Should we close this?

Yes.  As mentioned above, this is pretty much fundamentally impossible.  Extensions are written in an interpreted language (JS) and executed client-side.  This means that the code will always be able to be viewed by the user, and reasonably easily reverse-engineered.  This is the same for code used in the web.