Create GraphQL schema at root schema

rootSchema.js

import { makeExecutableSchema } from 'graphql-tools'
import merge from 'lodash.merge'

import {
  queries as fooQueries,
  resolvers as fooResolvers,
  typeDefinitions as fooTypeDefinitions,
} from './foo/schema'

import {
  queries as barQueries,
  resolvers as barResolvers,
  typeDefinitions as barTypeDefinitions,
} from './bar/schema'

const moduleTypeDefinitions = [
  fooTypeDefinitions,
  barTypeDefinitions,
]

const moduleQueries = [
  fooQueries,
  barQueries,
]

const schema = `
  type Query {
    ${moduleQueries.join('\n')}
  }

  ${moduleTypeDefinitions.join('\n')}
`

const resolvers = merge(fooResolvers, barResolvers)

export default makeExecutableSchema({
  typeDefs: [schema],
  resolvers,
})