GraphQL mutation without sub section

Question

I want to send graphql mutation request without sub section

mutation _ {
    updateCurrentUser(fullName: "Syava", email: "[email protected]")
}

and I am getting

{
  "errors": [
    {
      "message": "Field \"updateCurrentUser\" of type \"User\" must have a sub selection.",
      ... 
    }
  ]
}

add { id } to request works fine but I don't want

Also Schema code

const userType = new GraphQLObjectType({
  name: 'User',
  fields: () => ({
    id: { type: new GraphQLNonNull(GraphQLString) },
    fullName: { type: GraphQLString },
    email: { type: GraphQLString },
  }),
});

type: userType,
  args: {
    fullName: { type: GraphQLString },
    email: { type: new GraphQLNonNull(emailType) },
    password: { type: GraphQLString },
  },
  resolve: async (root, { fullName, email, password }, { rootValue }) => {
    const user = await User.findById(rootValue.req.user.id);

    ...

    return user;
  },

Answer 1

You define the type of the field to be UserType. Even though it's a mutation, it still follows the same rules and behavior as a query. Because UserType is an object type, it requires nested fields.

mutation _ {
  updateCurrentUser(fullName: "Syava", email: "[email protected]") {
    fullName
    email
  }
}
// would respond with { fullName: 'Syava', email: '[email protected]' }

If you don't want the mutation to return a User, you can declare its type to GraphQLBoolean for example -- that's a scalar and doesn't have any nested fields.

{
  type: GraphQLBoolean,
  args: {
    fullName: { type: GraphQLString },
    email: { type: new GraphQLNonNull(emailType) },
    password: { type: GraphQLString },
  },
  resolve: async (root, { fullName, email, password }, { rootValue }) => {
    const user = await User.findById(rootValue.req.user.id);
    user.fullName = fullName;
    user.password = password; // or hashed to not store plain text passwords
    return user.save(); // assuming save returns boolean; depends on the library you use
  }
}

Note that the best practice for mutations in GraphQL APIs is to return a "result" object with multiple fields, such as the mutated object itself (e.g. user), clientMutationId (per Relay spec), and others as needed. This makes it flexible so you could add more data in the future.

updateCurrentUser(fullName: "Syava", email: "[email protected]") {
  clientMutationId
  user {
    ...
  }
}