Make GraphQLResponse generic for e.g. type-safe integration tests

I’d recommend to make GraphQLResponse generic so that e.g. integration tests will be type safe, i.e. at https://github.com/apollographql/apollo-server/blob/main/packages/apollo-server-types/src/index.ts#L102:

export interface GraphQLResponse<T = any> {
  data?: Record<string, T> | null;
  ...

Then integration tests with e.g. Axios could be written in TypeScript as follows:

const response: AxiosResponse<GraphQLResponse<MyRecord> = await axios.post(url, requestBody, config);
const myRecord = response.data.data; // Type MyRecord

[glasser]

Yes, I think in general it would be good to move in the direction with aligning the types in Apollo Server (both for operations and resolvers) with things that can be generated by graphql-code-generator.

[glasser]

I think in practice folks will want to use a code generator such as GraphQL Code Generator or (not actively maintained) Apollo Codegen to generate response types rather than relying on GraphQLResponse. GraphQLResponse is more designed for writing a server that has to handle any GraphQL operation rather than use with specific operations.

It’s also only sorta typesafe, in the sense that you’re just basically asserting at compile time that the data you got back matches MyRecord without any runtime checks, right? So it’s not much better than just doing an as X in your code.

It does appear that changing any to unknown in the data and extensions field definitions is a change that typechecks at least in the context of the apollo-server repo. I think that might be a more accurate type.

I also think the change you suggested doesn’t quite make sense. Different keys under data will have different types. Did you mean something more like:

export interface GraphQLResponse<Data extends Record<string, unknown> = Record<string, unknown>> {
  data?: Data | null;