Add field directives on Info

[estrada9166]

It's possible to add a new field on info with the directives of that field?

Reason:

The main reason for this is that using a fieldResolver it'll be possible to add some extra logic on selected fields.

Example:

schema

directive @uppercase on FIELD_DEFINITION

type Me {
  email: String!
  username: String!
  fullName: String! @uppercase
  apiKey: String!
}

type Query {
  getMe: Me!
}

fieldResolver

function fieldResolver(value, args, ctx, info) {
  const result = defaultFieldResolver(value, args, ctx, info)

  const uppercase = info.fieldDirectives.find(directive => directive.name.value === 'uppercase') 

  if (uppercase) {
    return result.toUpperCase()
  }

  return result
}

using express-graphql

app.use('/graphql', (req, res) => {
  graphqlHTTP({
    schema,
    rootValue,
    graphiql: true,
    fieldResolver
  })(req, res)
})

Possible solution

In this method, we can get the directives from fieldDef.astNode.directives

graphql-js/src/execution/execute.js

Lines 696 to 717 in b8eb8de

	export function buildResolveInfo(
	exeContext: ExecutionContext,
	fieldDef: GraphQLField<*, *>,
	fieldNodes: $ReadOnlyArray<FieldNode>,
	parentType: GraphQLObjectType,
	path: ResponsePath,
	): GraphQLResolveInfo {
	// The resolve function's optional fourth argument is a collection of
	// information about the current execution state.
	return {
	fieldName: fieldDef.name,
	fieldNodes,
	returnType: fieldDef.type,
	parentType,
	path,
	schema: exeContext.schema,
	fragments: exeContext.fragments,
	rootValue: exeContext.rootValue,
	operation: exeContext.operation,
	variableValues: exeContext.variableValues,
	};
	}

---

Also, if this is accepted, I can work on that

[mjmahone]

We probably want a more comprehensive solution to getting a directive on various schema definitions.

I think the core idea here is right, but we'd also like to make it easy to access directives for things like type definitions with directives on them.

I think this is possible to do already by grabbing the astNode on the FieldDefinition, but I agree we could use some sort of easier access to the directives. Especially when you throw schema extensions and pure-JS-class created schemas into the mix.

[yaacovCR]

Fwiw graphql-tools has a getDirective method and cousins that might be helpful https://www.graphql-tools.com/docs/api/modules/utils_src#getdirective

[yukukotani]

Here is my dirty workaround:

import { getDirectives } from '@graphql-tools/utils';

function getDirectivesFromInfo(info: GraphQLResolveInfo) {
  const field = info.parentType.getFields()[info.fieldName];
  return getDirectives(info.schema, field);
}

It's better if GraphQLResolveInfo contains fieldDef so that we can just pass it to getDirectives function.