This is a calculator written in Javascript using the electron framework.
For the actual calculations the rust library leval is used.
The leval crate was compiled with emscripten
and the resulting file leval-js lies inside the app folder,
so ist does not need to be recompiled when building.
Just clone the repository and run
cd rechner
npm install
npm run package
This will create a directory build,
where inside another folder (depending on your target architecture) is the packaged app.