I am coding a data intense web app. So that means I cant be possibly doing any computations on sever- computation after every event involves huge data too large to be sent
Rather than using javascript for the client side logic, perhaps you could use an applet which was compiled from obfuscated java source code.
As far as your logic is concerned, you can use minification tools to make the code a bit hard to figure. This in no way shape or form completely protects your code, but just another tactic to fight back.
You cannot protect javascript files.
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I'm not aware of the specifics of your application, but there is almost certainly a way for the user to manipulate the data while it resides on your server.
You should open a new question with more details about your app.