Listening for specific cache updates

[turnerhayes]

I have a simple game app for a marble placement game (think something like tic-tac-toe). I use RTK Query to fetch the game object from the server, but I have a Socket.io client that updates the game using updateQueryData in response to certain socket messages. I'm trying to create a listener middleware that will respond to any time a new marble is added to the board (a field of the Game object).

There are a couple of issues I'm not sure how to address:

• Matching the action: it seems I can use api.internalActions.queryResultPatched.match, but the "internal" in the name makes me hesitant, as does the comment Internal actions not part of the public API. Note: These are subject to change at any given time. Is it "safe" to use this in listener logic?
• As far as I can tell, the listener only has access to the current state, after the cache has been patched. In that case, I wouldn't be able to know whether the change was a new marble being added to the board, or some other change. Is there currently a way to access the state before the patch, as well as after (apart from keeping a separate cache of all updates)?

[markerikson]

The "internal actions" are marked that way because we do reserve the right to change them, but realistically they don't change much. For queryResultPatched, I think we've tossed around the idea of turning it into a multi-item form instead like queryResultsPatched, but no immediate plans to do that.

And yes, the listener API does specifically have a getOriginalState method that will return the state before the action was processed by the reducer:

• https://redux-toolkit.js.org/api/createListenerMiddleware#store-interaction-methods