Prettify without leaving out the comments.

LS

Thanks for all effort invested into this power tool. The [Transcrypt](http://www.transcrypt.org) Python to JavaScript compiler uses the Google Closure Compiler, both to minify code and to convert es6 to es5.

We'd like to be able to use it also as a code prettyfier. So what would be needed then is the possibility to have it output for es5 or es6 WITHOUT STRIPPING COMMENTS, but just prettifying it.

Kind regards
Jacques de Hooge
jdeh@transcrypt.org