Pass previous object to resolvers

[cjelger]

Feature requests

Based on the documentation at https://graphql.org/learn/execution/#root-fields-resolvers, I expected that resolvers would always receive the parent/previous object as the first argument. However when I tested the library, the arguments received by the resolvers are actually (args, context, info).

This doesn't match the documentation, and is a serious limitation when one needs the parent object (for example, some id) in order to resolve children fields.

Is there a workaround or is this a known limitation?

[IvanGoncharov]

@cjelger Sorry for the confusion we definitely need to update our docs.
The short answer: you get the root object as this because resolver is called on this object.

This doesn't match the documentation

We actually have two types of resolvers:

1. specified in GraphQLObjectType fields and they get (parent, args, context, info)
2. resolvers specified on parent itself, in this case, their prototype is (args, context, info) and you can access parent using this.

[cjelger]

Thanks @IvanGoncharov, using this indeed works! I guess there might be a similar "mismatch" in the documentation when it comes to defining resolvers: the documentation seems to indicate that it's possible to define resolvers for types like Human at https://graphql.org/learn/execution/#scalar-coercion but this also doesn't work when defining the resolvers via the graphql method. Would this work when defining resolvers with GraphQLObjectType?

[IvanGoncharov]

the documentation seems to indicate that it's possible to define resolvers for types like Human at graphql.org/learn/execution/#scalar-coercion but this also doesn't work when defining the resolvers via the graphql method

@cjelger It should work, see here for a complete example: https://github.com/graphql/graphql-js/blob/eef0878d851f7b8a4392b031550a1080497c018c/src/__tests__/starWarsSchema.js

[cjelger]

@IvanGoncharov Thank you for your reply. I will try this again based on the example/test ... it's pretty much what I tried with minor differences.

[benallfree]

Hello, this one bit me too. I am using graphql-code-generator to generate Typescript resolvers. The resolver function signature matches the Graphql specification:

export type ResolverFn<TResult, TParent, TContext, TArgs> = (
  parent: TParent,
  args: TArgs,
  context: TContext,
  info: GraphQLResolveInfo
) => Promise<TResult> | TResult;

But when I write a simple resolver for graphql-js,

hello: (...args) => {
    console.log({ args })
    return {
      greeting: "Hello"
    }
  },

I see that the parent is not passed

args: [
   { ...variable info... },
   { ...context info... },
   { ... other info ... }
]

What is the recommended fix or workaround for this?

[benallfree]

Update: using makeExecutableSchema works perfectly.