Though you can use the assets in Shiny just as demonstrated in the examples, for performance reason you are better off following the methodology described in this document.

The idea is fairly simple. Copy the asset(s) into your www directory and source them in echarts4r. The ea_copy function will copy the file to your www and prompt you to create the directory if is not existing. The function also checks whether the file is already copied before doing so.

Remember to pass session to your server function

This will be much more performant and will work with any asset.