telling uglify to keep certain comments (using CodeKit)

Question

I'm using CodeKit to develop a WordPress theme. Of course I'd like to compress the LESS when it's compiled into CSS, but uglify.js removes all comments.

Does anyone know how to mark specific comments for preservation?

Edit: just wanted to add that after trying this in 2019 with CodeKit 3, the exclamation point trick works perfectly! (Allen Bargi's answer)

Contango

Answer 1

There's convention to put an exclamation mark right after the comment, to preserve it after minifying. you should use something like this:

/*!
  this comment will not be removed by minifiers
 */

The above answer is not valid anymore! things evolve!

Now you should add either @preserve or @license to the comment as mentioned by @texelate below.

Isaac

uglify doesn't respect that, not by default at least – Hebdomadary

@allen, this is not the default! – Gracious

This is wrong and shouldn't be the accepted answer. See my answer. – Pelisse

Just to help any newbies, this means /*@preserve comment here */ – Clearway

Coming back to this in 2019, and in CodeKit 3, this convention works beautifully! I can compress EVERYTHING now. Adding a CSS map helps me work out issues in the inspector too. – Contango

Answer 2

You need to add either @preserve or @license to the comments you want to keep. It doesn't honour /*!

Pelisse

Answer 3

You can use this way: --comments '/foo|bar/' : will keep only comments that contain "foo" or "bar". See more : https://github.com/mishoo/UglifyJS2#keeping-copyright-notices-or-other-comments

Alsworth

Answer 4

Half a year later, I hit the same issue and the exclamation mark trick did not "do the trick" for me. Neither any of the @preserve or @license options listed in uglify documentation. What did work is providing a regex on the commandline, e.g.:

uglifyjs file.js -c -m --comments '/^!|@(?:license|preserve)/' > file.min.js

Terminate

to respect more styles, including /*!, I used --comments '/(^!|@license|@preserve)/'. Test: uglifyjs -c -m --comments '/(^!|@license|@preserve)/' <<< 'test(); /* regular */ /*! important */ /*@license foo */ noop(); /*bar @preserve*/ // regular' – Dissimilitude