Search code examples
node.jsgraphqlgraphql-jsgraphql-subscriptions

Error: Can only create List of a GraphQLType but got: function GraphQLObjectType(config) , in GraphQL?


I am working on a demo project on GraphQL. But stuck here. I want to send the whole object as result. The object which I want to send is:

 exports.fakeDatabase = {
        1: {
            id: 1,
            name: 'Abhay',
            description:'This is Abhay\'s Database'
        },
        2: {
            id: 2,
            name:'Bankimchandra',
            description: 'This is Bankimchandra\'s Database'
        },
         3: {
            id: 3,
            name:'chandu',
            description: 'This is chandu\'s Database'
        }
    };

But when I am sending a request to access it I got Error:

Error: Can only create List of a GraphQLType but got: function GraphQLObjectType(config) {
    _classCallCheck(this, GraphQLObjectType);

    (0, _assertValidName.assertValidName)(config.name, config.isIntrospection);
    this.name = config.name;
    this.description = config.description;
    if (config.isTypeOf) {
      (0, _invariant2.default)(typeof config.isTypeOf === 'function', this.name + ' must provide "isTypeOf" as a function.');
    }
    this.isTypeOf = config.isTypeOf;
    this._typeConfig = config;
  }.

My code is-

schema.js:

const graphql = require('graphql');
var schema = {};
schema.getAllUser = new graphql.GraphQLObjectType({
    name: 'getAllUser',
    fields: {
        data:{type:new graphql.GraphQLList(graphql.GraphQLObjectType)}  // What should I do here to send the whole `fakeObject`
   }
})
module.exports = schema;

Query.js:

const graphql = require('graphql');
const userType = require('../schemas/schemaUserType');
const fakeDatabase = require('../assets/database');
const config = require('../config/config');


var schema = {};
module.exports = schema;
const queryType = new graphql.GraphQLObjectType({
    name: 'Query',
    fields: {
 getAllUser: {
            type: userType.getAllUser,
            args: {
            }, resolve: function () {
                return fakeDatabase.fakeDatabase;
            }
        }
    }
});
schema.queryTypq1 = new graphql.GraphQLSchema({ query: queryType });

server.js:

var app = require('express')();
var graphHTTP = require('express-graphql');
const schema = require('./queries/queryType');

app.use('/graphql', graphHTTP({
  schema: schema.queryTypq1,
  graphiql: true
}));

app.listen(4000, () => { console.log('Server is running on port: 4000'); });

Please make me understand what should i do to send the object fakeDatabase


Solution

    1. First fakeDatabase should be an array [] as the field data type is of GraphQLList in schema.getAllUser

    2. Second you have to create a GraphQLObjectType with the fields id, name and description


    may be something like this...

    exports.fakeDatabase = [
        {
            id: 1,
            name: 'Abhay',
            description: 'This is Abhay\'s Database'
        },
        {
            id: 2,
            name: 'Bankimchandra',
            description: 'This is Bankimchandra\'s Database'
        },
        {
            id: 3,
            name: 'chandu',
            description: 'This is chandu\'s Database'
        }
    ]
    

    and the GraphQLObjectType to represent the data

    const fakeDatabaseType = new GraphQLObjectType({
        name: 'fakeDatabase',
        fields: {
            id: { type: GraphQLID },
            name: { type: GraphQLString },
            description: { type: GraphQLString },
        },
    });
    
    
    const graphql = require('graphql');
    var schema = {};
    schema.getAllUser = new graphql.GraphQLObjectType({
        name: 'getAllUser',
        fields: {
            data: {
                type: new graphql.GraphQLList(fakeDatabaseType),
                resolve: function (obj) { /* obj is the parent object 
    containing the data passed from root query resolver */
                    return obj;
                },
            }
        }
    })
    module.exports = schema;
    

    const graphql = require('graphql');
    const userType = require('../schemas/schemaUserType');
    const fakeDatabase = require('../assets/database');
    const config = require('../config/config');
    
    
    var schema = {};
    module.exports = schema;
    const queryType = new graphql.GraphQLObjectType({
        name: 'Query',
        fields: {
            getAllUser: {
                type: schema.getAllUser,
                args: {
                }, resolve: function () {
                    return fakeDatabase; // passing the fake array
                }
            }
        }
    });
    schema.queryTypq1 = new graphql.GraphQLSchema({ query: queryType });
    

    Hope this Helps!!