I haven't heard about timm before, but it looks very similar to immer https://github.com/immerjs/immer, which is even recommended in the official React docs now
Nice, thanks to both of you for the tip. I always hated ImmutableJS's clunky API which is partly the reason why I switched from Redux to Mobx as the object assigning felt otherwise so icky. I have to check out if Immer is any better =).
[0] https://redux.js.org/style-guide/style-guide#use-immer-for-w...
[1] https://redux-toolkit.js.org/