V2: Update createProtobufSafeUpdater

[timostamm]

Closes #446. The signature of the provided updater function is changed to return a message instead of a message init shape.

[timostamm]

Adding undefined on line 59 supports a use-case with QueryClient.setQueryData:

If the value is undefined, the query data is not updated.

This means the following example compiles and works as expected (query data is not updated):

const queryKey = createConnectQueryKey({
  schema: ElizaService.method.say,
  input: { sentence: "hi" },
  transport: myTransport,
});

const newData: SayResponse | undefined = undefined;

const updater = createProtobufSafeUpdater(
  ElizaService.method.say,
  newData,
);

queryClient.setQueryData(queryKey, updater);

[timostamm]

We have to explicitly handle the undefined case now. In this example, we do not update query data if it does not exist.

If the goal is to create query data if none exists, the function could be updated to:

const safeUpdater = createProtobufSafeUpdater(schema, (prev) => {
  prev ??= create(schema.output);
  return {
    ...prev,
    int32Field: 999,
  };
});

We could move this logic into createProtobufSafeUpdater, and always provide data to the updater function. But then it isn't possible to update only existing query data. I'm not sure what's idiomatic here. WDYT, @paul-sachs?

[paul-sachs]

I think this new version is more idiomatic to react-query so I'm good with this updated behaviour.