If you run any syntax checking or minification tools, this will be immediately obvious. If you test your site in IE at all, this will be immediately obvious. If you record JS errors on your site, this will soon be obvious. If you record any kind of usage statistic, this will eventually be obvious.

Take it from someone who has experimented with cutesy formatting in the past[1]: you don't need to use cutesy formatting to solve this problem.

[1 | You can end class declarations with _:0} instead of a bare } to avoid the trailing comma issue. ]