@netizenconsultant I’ve already replied to the same question you asked privately (via email). However, I’ll post it here as well in case other people would have similar questions:
My wordpress already using CDN, wp-rocket, wp-smush the problem is the CSS and JS is minify become 1 file, so I dont know which one isnt used.
If you append a query string such as /?nocache to the URL, then each CSS/JS should load individually as WP Rocket won’t minify/combine the files, thus you can view each one loading. If you’re using Coverage DevTools (https://developers.google.com/web/tools/chrome-devtools/coverage) you will be able to notice the percentage of unused bytes from a file, which is sometimes 100%. Or you can make tests on Google PageSpeed using the query string URL and you will notice reports such as “Remove unused CSS” making reference to each file individually, not to just one. Here’s an example of using Coverage to determine of Gutenberg CSS library is needed or not: https://assetcleanup.com/docs/how-to-check-if-gutenberg-blocks-css-file-is-needed-or-not/
1. Can the pro version of assets clean up choose automatically which CSS and JS that is not used?
No, you have to go through some trial and error and use tools like the one I mentioned (e.g. Coverage DevTools) to determine if you need the file loaded or not, often in “Test Mode”. It all depends on your confidence. Some people (e.g. developers with experience) don’t need to use “Test Mode” as they are confident what plugins are needed on the page and which aren’t.
2. If the CSS and JS already minify by wp-rocket and served using CDN, will the pro plugin still worked?
Yes, it will still work and if you’re happy with WP Rocket’s minify CSS/JS feature, then you don’t have to also have it enabled in Asset CleanUp Pro and you can strip the “fat” my unloading useless CSS/JS files and in the end, the resulting files from WP Rocket (as you mentioned) will be much smaller and as a result, download much faster by the browser 😉
