# WP Rocket | Simple LoadCSS Preloader
### by [Ensemble Group](https://ensemblegroup.net)  

Simple high performance plugin to enhance WP Rocket's css output to use the loadCSS preload polyfill.  
This will ensure **any css** being loaded via the page output **is deferred**, and utilizing a preload [rel] attribute.  
Note: This will not affect admin pages. It's designed only to process front-end pages.  
  
It is recommended to enable the WP Rocket setting for "Optimize CSS", which will provide your pages with inline Critical-CSS.  
That way an unstyled flash is not seen on page load (if properly configured of course).  

**This plugin will boost your [Lighthouse](https://developers.google.com/web/tools/lighthouse/) and [PageSpeed Insight](https://developers.google.com/speed/pagespeed/insights/) scores.**
  
## Plugin Mission 
We firmly believe that [WP Rocket](https://wp-rocket.me/) should implement this as a **feature** of their plugin.  
If that takes place, we will update this plugin to mark it as deprecated.  

## Requirements: 
* If you intend for logged-in users to see the effect, you must enable WP-Rocket's setting called "caching for Logged-In Users"
* This plugin relies on having loadCSS present. It comes with it built in.
* * Alternatively, you can run the plugin without WP-Rocket, despite it's intended purpose.    (>^.^)>

## Features:  
* [FilamentGroup's LoadCSS(v2.0.1)](https://github.com/filamentgroup/loadCSS/tree/v2.0.1) inline injector 
  (optional - see settings page next to WP Rocket), *triggered via wp_head*  
* High performance Regular Expression approach to process WP Rocket's (php's) output buffer, to replace stylesheets with the appropriate loadCSS syntax  
* Option to enable the buffer processor when you don't have WP Rocket installed.  
** This will respect AMP pages, and Yoast Sitemap output (by not executing). No other considerations have been implemented.  

No fluff. Just a robust loadCSS implementation.  

## Last tested with:
* WP Rocket 3.1.x
* WordPress 4.9.x

## Dependencies
* WP Rocket  (optional via settings)  
* file_get_contents() php function  (if included loadCSS lib is used via options -- default = yes)

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You can see how it works, & measure the performance, with this(via repl.it): [Run the Plugin's code](https://repl.it/@ensemblebd/WPRocketLoadCSSMeasurement)  
Just paste your own page's url or html into the appropriate variable @ the top.  

And you can test this plugin's regex as well: [Wordpress.com html - links filtered by regex](https://regex101.com/r/xsugT7/1/)  

Github link is here: [Click](https://github.com/ensemblebd/wp-rocket-loadcss)