Apollo-resolver.js

// define the graphql query
const UserQueryDefs = gql`
  extend type Query {
    user(id: ID): User
  }
`;

// graphql resolver
async user(_, args, context): Promise<any> {
  // return the requested user
  return getRepository(User).findOne(args.id);
}

// graphql resolver which only selects 
async user(_, args, context): Promise<any> {
  // get an array of selected fields 
  const selectedFields = info.fieldNodes[0].selectionSet.selections.map((field: any) => field.name.value);
  
  // return the requested user - with only the selected fields
  return getRepository(User).findOne({ 
    select: selectedFields, 
    where: { id: args.id } 
  });
}