Resolver args type not correctly propagated from GraphQLObjectType

[harrysolovay]

I'm running into issues relating to the inference of arguments and return types from within a given GraphQLObjectType.

My query interface looks like this:

interface Query {
  tweets: Tweet[];
  user: User;
}

And my schema like this:

export const schema = new GraphQLSchema({
  query: new GraphQLObjectType<Context, Query>({
    fields: {
      tweets: {
        resolve: async (_0, args) => {
          // `tweets` resolution here
        },
        type: new GraphQLList(TweetType),
      },
      user: {
        args: {
          id: {type: GraphQLID},
        },
        resolve: async (_0, args) => {
          // `user` resolution here
        },
        type: UserType,
      },
    },
    name: "Query",
  }),
});

The tweets query is meant to accept no arguments, whereas the user query accepts the user's id. So I specify the 3rd generic argument, which I hoped would map to the correct fields:

export const schema = new GraphQLSchema({
- query: new GraphQLObjectType<Context, Query>({
+ query: new GraphQLObjectType<Context, Query, {tweets: undefined; user: {id: string}}>({
    fields: {
...

Although I expect for those types to flow through to their respective resolver arguments, they do not. Instead, the entire map flows through:

While I could provide a union of the two types, this lacks specificity, and I was wondering if there's a better way?

Additionally, (perhaps this merits another issue), the resolver return types aren't inferred either (I have to manually append the return signature).

-         resolve: async (test, args) => {
+         resolve: async (test, args): Promise<Tweet[]> => {
          try {
            const tweets = await firestore.collection("tweets").get();
            return tweets.docs.map((tweet) => ({id: tweet.id, ...tweet.data()})) as Tweet[];
          } catch (error) {
            throw new ApolloError(error);
          }
        },
        type: new GraphQLList(TweetType),
      },
      user: {
        args: {
          id: {type: GraphQLID},
        },
-       resolve: async (_0, args) => {
+       resolve: async (_0, args): Promise<User> => {

Any help or advice would be greatly appreciated! Thank you!

Kind regards,

Harry

[IvanGoncharov]

@harrysolovay Thanks for reporting 👍
Totally agree that 3rd-argument is very confusing so I removed TArgs in #2488.
It was added by DefinetlyTyped maintainers and we inherited when we adopted TS typings from them.

As for the long term solution, there is a discussion about adding more complex TS typings in #2188
Also if you goal to have maximum type safety in TS I would suggest using
https://github.com/MichalLytek/type-graphql or https://github.com/graphql-nexus/schema