How to get requested fields inside GraphQL resolver?

Question

I am using graphql-tools. After receiving a GraphQL query, I execute a search using ElasticSearch and return the data.

However, usually the requested query includes only a few of the possible fields, not all. I want to pass only the requested fields to ElasticSearch. First, I need to get the requested fields.

I can already get the whole query as a string. For example, in the resolver,
const resolvers = {
  Query: {
    async user(p, args, context) {
      //can print  query as following
      console.log(context.query)                
    }
    .....
  }
}

It prints as
query User { user(id:"111") { id  name address } }


Is there any way to get the requested fields in a format like
{ id:"",  name:"", address:"" }

Snehal Kumar · Accepted Answer

In graphql-js resolvers expose a forth argument called resolve info. This field contains more information about the field. From the GraphQL docs GraphQLObjectType config parameter type definition: // See below about resolver functions. type GraphQLFieldResolveFn = ( source?: any, args?: {[argName: string]: any}, context?: any, info?: GraphQLResolveInfo ) => any type GraphQLResolveInfo = { fieldName: string, fieldNodes: Array<Field>, returnType: GraphQLOutputType, parentType: GraphQLCompositeType, schema: GraphQLSchema, fragments: { [fragmentName: string]: FragmentDefinition }, rootValue: any, operation: OperationDefinition, variableValues: { [variableName: string]: any }, } In the fieldNodes field you can search for your field and get theselectionSetfor the particular field. From here it gets tricky since theselectionscan be normal field selections, fragments or inline fragments. You would have to merge all of them to know all fields that are selected on a field.

Ritesh swamy · Answer

There is an info object passed as the 4th argument in the resolver. This argument contains the information you're looking for. It can be helpful to use a library as graphql-fields to help you parse the graphql query data: const graphqlFields = require('graphql-fields'); const resolvers = { Query: { async user(_, args, context, info) { const topLevelFields = graphqlFields(info); console.log(Object.keys(topLevelFields)); // ['id', 'name', 'address'] }, };

GraphQL

Similar Questions

In GraphQL what's the meaning of edges and node?

How to check permissions and other conditions in GraphQL query?

Apollo/GraphQL field type for object with dynamic keys

On a mission to build Next-Gen Community Platform for Developers

Facebook

Twitter

Linkedin

Instagram