useSWRSubscription: How to reduce new values?

[imownbey]

useSWRSubscription is helpful especially its deduping of multiple calls with the same key. One issue I am facing when trying to use it with supabase though is subscriptions are only called with new data (update, insert or delete) and not with all of the data like in Firebase.

I need to act on some prefetched data and either remove, add or update it to return the fully formed dataset. The only way I can think of to do this right now is combining useSWRSubscription with a useState like

const [state, setState] = useState(["foo", "bar"])

const { data } = useSWRSubscription("key", (key, {next}) => {
  supabase.channel("updates").on((update) => {
    switch (update.type) {
      case "insert":
        next({type: "insert", value: update.value})
        break;
      case "delete":
        next({type: "delete", id: update.old.id})
   ... etc
})

useEffect(() => {
  switch (data.type) {
     case "insert":
       setState((prev) => [...prev, data.value]
       break;
  }
}, [data.type, date.value, data.id])

I ideally would have a like useSWRReducer() that I can pass initial data into and then act on or something? I can probably make something similar for myself by using useReducer and useSWRSubscription + useEffect but I want to make sure I am not missing some intended way of using useSWRSubscription.
which seems kind of gnarly.