This is the new version of the RepRapFirmware Configuration Tool. It is written in TypeScript using the Vue 3 and Bootstrap-Vue libraries.
Vue recommends VSCode + Volar.
TypeScript cannot handle type information for .vue imports by default, so we replace the tsc CLI with vue-tsc for type checking. In editors, we need Volar to make the TypeScript language service aware of .vue types.
If the standalone TypeScript plugin doesn't feel fast enough to you, Volar has also implemented a Take Over Mode that is more performant. You can enable it by the following steps:
- Disable the built-in TypeScript Extension
- Run 
Extensions: Show Built-in Extensionsfrom VSCode's command palette - Find 
TypeScript and JavaScript Language Features, right click and selectDisable (Workspace) 
 - Run 
 - Reload the VSCode window by running 
Developer: Reload Windowfrom the command palette. 
See Vite Configuration Reference.
npm installnpm run devnpm run build