Rocket Loader priorities your website’s content (text, images, fonts etc) by deferring the loading of all of your JavaScript until after rendering. 

On pages with JavaScript, this results in a much faster loading experience for your users and improves the following performance metrics:

• Time to First Paint (TTFP)
•  Contentful Paint (TTFCP)
•  Meaningful Paint (TTFMP)
• Document Load

To learn more about the latest version of Rocket Loader visit our blog: Cloudflare

Addition optional configuration:

• If you have a Content Security Policy, you will need to update.

It is to allow Rocket Loader to run: What is Content Security Policy (CSP), and how can I use it with Cloudflare?

• If you have specific scripts you want to not optimise, you can do this by modifying your HTML script tags. How can I have Rocket Loader ignore specific JavaScripts?