Default mutation function using key

[honzahruby]

Similar to the default query function, we'd love the ability for the default mutation function to access the mutation key. Currently, it can only access the variables passed by the user.

Is it a conscious decision, given the mutation key is optional, while in queries it's required? Or is it something to consider adding? 🙏

[honzahruby]

@TkDodo any idea why it's so? 🙏

[TkDodo]

we don't pass anything to the mutationFn because the mutationFn takes variables passed in by users already.

[honzahruby]

I know it's not possible now, but how about passing some extra context as a second argument then?

Using the default query function is great because we don't need to generate any extra code for our API client, but it's unfortunate the same doesn't work for mutations 😕

[honzahruby]

Sorry for pinging you again @TkDodo, I've put together a simple code example to better explain what I'm trying to achieve.

Basically going from this (where the key is optional)

const useDeleteUser = () => useMutation({ mutationKey: ['users', 'delete'], mutationFn: async (id: string) => apiClient.users.delete(id), });

to this

const reactQueryClient = new QueryClient({ defaultOptions: { mutations: { mutationFn: async (variables, { mutationKey: [controller, method] }) => apiClient[controller][method](variables), }, }, }); const useDeleteUser = () => useMutation({ mutationKey: ['users', 'delete'], });

which mimics what's already possible for queries.

Is it something you would consider adding? 🙏

[TkDodo]

I'll think about it, yes

[honzahruby]

Closing as this has been implemented in #9615. Huge thank you to @TkDodo, @joshuaellis and others involved 👏