Improve TypeScript support and definitions

[dsebastien]

Hello,

In my project I'm currently giving Apollo Server (express) a try and am having some difficulties finding how to write type-safe mutation resolvers.

Given the following schema:

type Query {
    ...
}

type Mutation {
    reserveDeal(input: ReserveDealInput!): ReserveDealPayload
}

input ReserveDealInput {
    dealId: String!
}

type ReserveDealPayload {
    result: Boolean
}

If I write the following then my code compiles and I do have some type safety with the reserveDeal input

const resolvers = {
    Query: {
        deals: () => dummyDeals
    },
    Mutation: {
        //{ input: ReserveDealInput }
        reserveDeal: (root: any, arg: { input: ReserveDealInput } | any): ReserveDealPayload => {
            console.log("Reserving deal: ", arg.input.dealId);
            return {result: true};
        }
    }
};

The problem is the | any that I had to add to work around the following compilation issue with makeExecutableSchema:

src/index.ts(81,59): error TS2345: Argument of type '{ typeDefs: string; resolvers: { Query: { deals: () => { id: string; title: string; description: ...' is not assignable to parameter of type 'IExecutableSchemaDefinition<any>'.
  Types of property 'resolvers' are incompatible.
    Type '{ Query: { deals: () => { id: string; title: string; description: string; }[]; }; Mutation: { res...' is not assignable to type 'IResolvers<any, any> | IResolvers<any, any>[] | undefined'.
      Type '{ Query: { deals: () => { id: string; title: string; description: string; }[]; }; Mutation: { res...' is not assignable to type 'IResolvers<any, any>[]'.
        Property 'includes' is missing in type '{ Query: { deals: () => { id: string; title: string; description: string; }[]; }; Mutation: { res...'.

Do you have any ideas/pointers to help me improve this code towards better type safety?

[sundeer]

same here - what's the 'includes' property?

[lucasbento]

I'm getting the same, did anyone manage to solve this?

[lucasbento]

Similar issues: #372, #583 & DefinitelyTyped/DefinitelyTyped#21359.

[stubailo]

Also related: #404

[affanshahid]

Updates?

[FedeBev]

Any news?

Should be enough to change IFieldResolver definition from

export declare type IFieldResolver<TSource, TContext, TArgs = {
    [argument: string]: any;
}> = (source: TSource, args: TArgs, context: TContext, info: GraphQLResolveInfo & {
    mergeInfo: MergeInfo;
}) => any;

to

export declare type IFieldResolver<TSource, TContext, TArgs = any> = (source: TSource, args: TArgs, context: TContext, info: GraphQLResolveInfo & {
    mergeInfo: MergeInfo;
}) => any;

Shouldn't be?

[yaacovCR]

Pull requests now welcome!

[yaacovCR]

This looks potentially fixed in #1307, closing for now, please check out graphql-tools@next and reopen as necessary.