Allow to specify field type as a string

Currently

graphql.js expects type option to be an instance of GraphQLType (GraphQLInputObjectType, GraphQLObjectType, etc). Example:

const AnotherType = new GraphQLObjectType({ ... })
const Type = new GraphQLObjectType({
  name: 'MyType',
  fields: {
    anotherType: { type: AnotherType }
  }
})

Desired

In order to split application into modules (which may have circular references in GraphQL types) it’d be helpful to be able to specify type parameter in fields as a string. Updated example:

const Type = new GraphQLObjectType({
  name: 'MyType',
  fields: {
    anotherType: { type: 'AnotherType' } // AnotherType is referenced by its name
  }
})

Workaround

Currently when nodejs modules have circular reference, I can use ugly workaround: calling require in fields thunk:

const Type = new GraphQLObjectType({
  name: 'MyType',
  fields: () => ({
    anotherType: { type: require('anotherModule').AnotherType } 
  })
})

Implementation details

We can add a restriction, that types which a referenced by their name must be included in types option of GraphQLSchema constructor:

const schema = new GraphQLSchema({
  types: [/* specify types that were referenced by their name */],
  query: ...,
  mutation: ...
  subscription: ...
})

So, then the flow is this:

1. Walk over types array, add them into typeMap
2. Walk over Query, Mutation, Subscription recursively and resolve types

[sibelius]

I’m trying to split my types in many packages and it is hard to do using type instances when you can’t avoid circular references in types (most GraphQL schemas that I know).

thunk solves part of this, but it makes it hard to add or remove fields to existing types

you can do something like this

addFields(graphqlObjecttypes, newFields) because it would cause a circular dep to resolve the thunk when adding new fields

we could have a helper to handle both string and graphql object type

export const getObjectType = (typeOrString) => {
   if (typeOrString instanceof GraphQLObjectType) {
     return typeOrString;
   }

    return typeMap[typeOrString];
}

[stalniy]

So, is this something you guys want to see in graphql.js? just don’t want to waste time in case you are against it 😃