Just tried it out. Smooth sailing! A couple remarks: 1) It would be nice to explain some of the warnings. I had

    myFunction() {
        for (var x in xs) { .. }
        for (var x in xs2) { .. }
    }

it would complain about "Duplicate declaration of variable 'x'". Understandable, but then I'd like to know the javascript context information (apparently x is not in a sub-scope (as in most languages), but in the main function scope). 2) GitHub integration would be nice. A button when looking at source in GitHub which annotates the code with warnings would be quite an improvement over the current view.