> You would really have to go out of your way to make that happen, though. React has a feature for batching state updates together to prevent unnecessary rerenders if all of the updates occur together.

These batched state updates only happen "within React's walls", right?

So for example, say you had an RxJs observable that omitted a list of items to display. When you first subscribe, it emits say, ten items, one by one, but all in the same browser tick. It may emit items later in the future as well.

In this case, each of the initial emitted items triggers a full rerender and you get the O(N^2) behavior, correct? My point here isn't that this is the end of the world, but just that it isn't that crazy to say that it might happen.