https://github.com/codecat/beamngts My friend who is working on making custom scripts for my Terrain I am working on, made typescript declarations for BeamNG's LUA environment. These can be used in combination with TypescriptToLua: https://typescripttolua.github.io/ These aren't 100% complete, but are a work in progress, Hope they are useful! If you have any questions feel free to post them on the Github page, or here.
