One thing is Data Oriented Programming, I mentioned here:
https://forum.defold.com/t/shooting-circles-defold-ecs-game-example/77465/9?u=pawel
It’s literally a rule of DOP to have immutable data.
The FBP was mentioned in that post by David, I just got into this, can’t really share anything really good yet, just reading Internet 
maybe @dlannan, you can? I looked up your deity project, but it’s too complex for me yet 