Package Exports

graphql-fields

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (graphql-fields) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

graphql-fields

Turns GraphQLResolveInfo into a map of the requested fields. Flattens all fragments and duplicated fields into a neat object to easily see which fields were requested at any level.

Usage

Schema Type definition

const graphqlFields = require('graphql-fields');
const graphql = require('graphql')

const UserType = new graphql.GraphQLObjectType({
    name: 'User',
    fields: {
        profile: {type: new graphql.GraphQLObjectType({
          name: 'Profile',
          fields: {
            firstName: {type: graphql.GraphQLString},
            lastName: {type: graphql.GraphQLString},
            middleName: {type: graphql.GraphQLString}
          }
        }),
        email: {type: graphql.GraphQLString},
        id: {type: graphql.GraphQLID}
    }
});

module.exports = new GraphQLSchema({
    query: new GraphQLObjectType({
        name: 'Query',
        fields: () =>
            Object.assign({
                user: {
                    type: UserType,
                    resolve(root, args, context, info) {
                        console.log(
                            JSON.stringify(graphqlFields(info), null, 2);
                        );
                        ...
                    }
                }
            })
    })
})

Query

{
  user {
    ...A
    profile {
      ...B
      firstName
    }
  }
}

fragment A on User {
  ...C
  id,
  profile {
    lastName
  }
}

Fragment B on Profile {
  firstName
}

Fragment C on User {
  email,
  profile {
    middleName
  }
}

will log

{
  "profile": {
    "firstName": {},
    "lastName": {},
    "middleName": {}
  },
  "email": {},
  "id": {}
}

Why

An underlying REST api may only return fields based on query params.

{
  user {
    profile {
      firstName
    },
    id
  }
}

should request /api/user?fields=profile,id

while

{
  user {
    email
  }
}

should request /api/user?fields=email

Implement your resolve method like so:

resolve(root, args, context, info) {
    const topLevelFields = Object.keys(graphqlFields(info));
    return fetch(`/api/user?fields=${topLevelFields.join(',')}`);
}

Tests

npm test