formatParams replacement and GraphQLExtension

[richgilbank]

Hi folks!

It looks like the removal of formatParams from the ApolloServer constructor options eliminates the approach some have taken to omit __typename from mutations derived from query results.
See here: apollographql/apollo-client#1564
This may be a bit of an edge case, but there seems to be a number of issues relating to the following situation:

• Query for a data set from Apollo Server, using Apollo Client.
• [__typename is added to the query result]
• Locally modify the data set and send it back as a mutation.
• Rejection due to __typename not being defined in the typedefs.

One workaround to this has historically been using formatParams to omit the __typename key from any incoming variables, so it doesn't have to happen on the client side (and consequently doesn't have to be implemented in every consumer).
@evans mentioned "The experimental, non-public graphql-extensions provides a more structured and flexible way of instrumenting Apollo Server", though I haven't seen any implementations or docs that might help to do so.

So, I suppose any of the following would really help to clarify usage with the new approach:

• Add a demo or docs for graphql-extensions
• Add tests for graphql-extensions
• Document extensions publicly with the ApolloServer docs

Or is it a short-term workaround that shouldn't be documented yet?
Thanks!

[martijnwalraven]

The reason we removed formatParams is that it depended on implementation details of Apollo Server that we don't want to be bound to. graphql-extensions is not an API we're committed to either, but it could be used as a short term workaround. We're working on a more flexible extension API for the next version of Apollo Server, so hopefully we'll have a more permanent solution in a few weeks.

To make sure that covers your use case, do I get it right you want to modify variables for an incoming GraphQL request?

[richgilbank]

Ah, ok so it probably doesn't make sense to document it for now then.
Yes, exactly...walking through the variables on an incoming request to omit any nested __typename keys.

[terion-name]

No solution yet? My entire app can't work without this

[jbaxleyiii]

Hey @richgilbank @terion-name this is something that can be done using the new request pipeline that is supported now and will be getting a lot more support (and docs) in the future!