TypeScript
By default Scar / Lua is used for Age of Empires 4 scripting. The TypeScriptToLua (TSTL) project can convert TypeScript to Lua.
TypeScript mod example / template which can be used as a starting point: https://github.com/aoemods/aoe4-typescript-template
Types repository which the above template uses: https://github.com/aoemods/aoetypes
Project using TypeScript for scenario scripts: https://github.com/aoemods/dodge-mod