From what I gathered, you are looking for someone who can develop your website's frontend in JS because it's much faster than other languages. JS is however quite difficult to debug, which means that the developer who decides to take on this task is gonna have a lot on their plate.
What I propose to you is to have the entire thing done in GWT. GWT stands for Google Web Toolkit, which is the same framework Google uses for its web apps.
GWT would allow the developer (me) to write everything down in Java, both frontend and backend, at runtime however the frontend gets "converted" to JS. GWT also provides by default code obfuscation and optimisation which makes everything fast and reliable as for the hacker issue, GWT already provides its own authorisation mechanism.