Conditional CSS preload

[ggeorgovassilis]

Issue #30 preloads prettify.css. This has a drawback when optimisations like the Fast Velocity Minify plugin are active, which bundles all CSS into a single file. In that case the preloader still fetches prittify.css issuing an unnecessary http request in every page. Preloading should be conditional on a setting.

[kasparsd]

Thanks for reporting the issue!

The prettify.css is loaded via JS instead of wp_enqueue_script() so it shouldn't be possible for concatenation plugins to include it in the bundle. I'm not seeing the issue with https://github.com/kasparsd/minit for example.

You bring up a good point, though -- that preload only makes sense when the prettify.css is going to be actually used. I wonder if the prettify library loads it on every page or we're triggering false preloads when the CSS file isn't actually needed.

[ggeorgovassilis]

Thank you for the quick response. I worked around the issue by commenting prettify_preload_code_styles

[kasparsd]

I just posted an alternative solution in the wiki that should allow you to keep the plugin updated and have the preload disabled.

Also, could you please confirm if and how prettify.css get's included in the FVM bundle even when it's added via JS? Is that because of that preload rule?

[ggeorgovassilis]

Also, could you please confirm if and how prettify.css get's included in the FVM bundle even when it's added via JS? Is that because of that preload rule?

It's <link rel="preload"> inlined into the page's html. The FVM bundle already includes prettify.css, so removing the preloader doesn't affect functionality.

[kasparsd]

Shouldn't it remove the preload tag if it already inlined its content?