I was just trying out react-sweet-state as it looks interesting and created a small to do list app to play with it.

I put an array of Todo objects in an array as the state of the store.
This produces no errors from typescript and even runs without error until you setState new values of the state.

The state of the store being an array is not supported as I later discovered in the react-sweet-state documentation under setState().

I think you might help developers by either tightening the types allowed for the state of store, or maybe adding a runtime warning in development mode from react-sweet-state.

I stripped down the app I was playing with to make a small example to demonstrate the behavior I am describing.
https://codesandbox.io/s/eloquent-hill-vh4xb?file=/src/App.tsx

If you change the text of a to do item it calls setState and that crashes this app because after set state the value of state is of the form { 0: [Todo1, Todo2] }

I quite like sweet state so far 👍
Thank you for making it available.