Create custom menus, commands, plugins, systems, basically anything with scripts in Javascript! With multithreading and Folia support! Everything is fully documented in the documentation!
Source code: https://openjs.wiki.gd/example-scripts/skull-grabber-dialog-ui
Source code: https://openjs.wiki.gd/example-scripts/entity-spawn-menu
Source code: https://openjs.wiki.gd/example-scripts/benchmarker