I've started to create mods for game:
https://store.steampowered.com/app/1318690/shapez/
copy the js file to your mod folder of the game ( by deault using Steam version on Linux: /home/%username%/.local/share/shapez.io/mods/ )
I've learnt it form: https://github.com/tobspr-games/shapez.io/tree/master/mod_examples
https://github.com/tobspr-games/shapez.io
https://github.com/tobspr-games/shapez.io/tree/master/mod_examples