Use natural sort for sorting selectors

It appears that clean-css now sorts selectors, whereas it didn’t previously. It seems to be using a simple naive sort, which has somewhat unpleasant results when the selectors have numbers in them. For example:

.col-lg-1,.col-lg-10,.col-lg-11,.col-lg-12,.col-lg-2,.col-lg-3,.col-lg-4,.col-lg-5,.col-lg-6,.col-lg-7,.col-lg-8,.col-lg-9 {...}

Would it be possible to use natural sorting instead, to obtain more pleasant results? For example:

.col-lg-1,.col-lg-2,.col-lg-3,.col-lg-4,.col-lg-5,.col-lg-6,.col-lg-7,.col-lg-8,.col-lg-9,.col-lg-10,.col-lg-11,.col-lg-12 {...}

Here are a couple libs I found on npm that might do the job:

• https://www.npmjs.com/package/javascript-natural-sort
• https://www.npmjs.com/package/natural-compare-lite

[jakubpawlowicz]

Ready on master and soon in 4.0. Available via:

// API
new CleanCSS({ level: { 1: { selectorsSortingMethod: 'natural' } } }).minify(...)

# CLI
%> cleancss -O1 selectorsSortingMethod:natural ...

[jakubpawlowicz]

Thanks @jessehouchins for your input. I’m still considering it and leaving it open as an enhancement.