Hi @StudioRTP
For image optimisation, there is the use of the imageProcessor ( Image Processor ).
And there is a Treehouse snippet that shows an example using this for different device optimisation: Device Image Processing
For CSS and JS optimisation/pre-processing, there is nothing within Treepl.
You could look at a local pre-processing workflow or CDN solutions.
Cloudflare do have the option to optimise/compress CSS/JS along with various other website performance options ( https://www.cloudflare.com/website-optimization/ ) - including their own image optimisation service too.
Hope that helps.