gistfile1.txt

# somewhere in schema definition
type User {
   name: String!
   lastname: String!
   fullname: String!
}


// somewhere in server code

const resolvers = {
     Query: {
        getUsers() {
          return users
        }
     },
     User: {
       fullname: {
       
         /** 
         * without this you are force to set in the query name and lastname everytime you request 
         * fullname, or it will not receive the value here and get undefined insted
         */
           fragment: `... on User { name, lastname }`,
           resolve: (parent, args, context, info ) {
               return parent.name + return parent.lastname
           }
       }
     }
 }
 })