Hi I am trying to learn GraphQL language. I have below snippet of code.
// Welcome to Launchpad! // Log in to edit and save pads, run queries in GraphiQL on the right. // Click "Download" above to get a zip with a standalone Node.js server. // See docs and examples at // graphql-tools combines a schema string with resolvers. import { makeExecutableSchema } from 'graphql-tools'; // Construct a schema, using GraphQL schema language const typeDefs = ` type User { name: String! age: Int! } type Query { me: User } `; const user = { name: 'Williams', age: 26}; // Provide resolver functions for your schema fields const resolvers = { Query: { me: (root, args, context) => { return user; }, }, }; // Required: Export the GraphQL.js schema object as "schema" export const schema = makeExecutableSchema({ typeDefs, resolvers, }); // Optional: Export a function to get context from the request. It accepts two // parameters - headers (lowercased http headers) and secrets (secrets defined // in secrets section). It must return an object (or a promise resolving to it). export function context(headers, secrets) { return { headers, secrets, }; }; // Optional: Export a root value to be passed during execution // export const rootValue = {}; // Optional: Export a root function, that returns root to be passed // during execution, accepting headers and secrets. It can return a // promise. rootFunction takes precedence over rootValue. // export function rootFunction(headers, secrets) { // return { // headers, // secrets, // }; // }; Request:
{ me } Response:
{ "errors": [ { "message": "Field \"me\" of type \"User\" must have a selection of subfields. Did you mean \"me { ... }\"?", "locations": [ { "line": 4, "column": 3 } ] } ] } Does anyone know what I am doing wrong ? How to fix it ?
1 Answer
A GraphQL object type has a name and fields, but at some point those fields have to resolve to some concrete data. That's where the scalar types come in: they represent the leaves of the query.
GraphQL requires that you construct your queries in a way that only returns concrete data. Each field has to ultimately resolve to one or more scalars (or enums). That means you cannot just request a field that resolves to a type without also indicating which fields of that type you want to get back.
That's what the error message you received is telling you -- you requested a User type, but you didn't tell GraphQL at least one field to get back from that type.
To fix it, just change your request to include name like this:
{ me { name } } ... or age. Or both. You cannot, however, request a specific type and expect GraphQL to provide all the fields for it -- you will always have to provide a selection (one or more) of fields for that type.
