Cannot set property 'name' of undefined (Nodejs Graphql)

Question

I'm trying to learn Graphql by making a simple Node application with some dummy data to test with.

When I try to run Node I get the following error

TypeError: Cannot set property 'name' of undefined
at GraphQLObjectType (/Users/BorisGrunwald/Desktop/programmering/Javascript/Node/graphQLServer/server/node_modules/graphql/type/definition.js:480:15)
at Object.<anonymous> (/Users/BorisGrunwald/Desktop/programmering/Javascript/Node/graphQLServer/server/schema/schema.js:22:23)
at Module._compile (internal/modules/cjs/loader.js:721:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:732:10)
at Module.load (internal/modules/cjs/loader.js:620:32)
at tryModuleLoad (internal/modules/cjs/loader.js:560:12)
at Function.Module._load (internal/modules/cjs/loader.js:552:3)
at Module.require (internal/modules/cjs/loader.js:657:17)
at require (internal/modules/cjs/helpers.js:20:18)
at Object.<anonymous> (/Users/BorisGrunwald/Desktop/programmering/Javascript/Node/graphQLServer/server/app.js:6:20)

These are the only two files in my project:

app.js

const express = require('express');
const graphqlHTTP = require('express-graphql');

const app = express();

const schema = require('./schema/schema');

app.use('/graphql',graphqlHTTP({
    schema
}));

app.listen(4000,() => {
    console.log('listening on port 4000');
});

schema.js

const graphql = require('graphql');   

const { GraphQLObjectType, GraphQLString, GraphQLSchema } = graphql;


const dummyData = [
    {name: 'Name of the Wind', genre: 'Fantasy', id:'1'},
    {name: 'The Final Empire', genre: 'Fantasy', id:'2'},
    {name: 'The Long Earth', genre: 'Sci-Fi', id:'3'}
];

const BookType = new GraphQLObjectType({
    name:'Book',
    fields: () => ({
        id: {type : GraphQLString},
        name: {type: GraphQLString},
        genre: {type: GraphQLString}
    })
});

const RootQuery = GraphQLObjectType({
    name:'RootQueryType',
    fields: {
        book:{
            type:'BookType',
            args: {id:{type:GraphQLString}},
            resolve(parent,args) {
                return dummyData.find(book => book.id === args.id)
            }
        }
    }
});


module.exports = new GraphQLSchema({
    query:RootQuery
});

Can any of you spot the error? Thanks in advance.

Mubeen Khan · Accepted Answer · 2019-01-30 11:49:03Z

17

while creating RootQuery object you just missed the "new" keyword for GraphQLObjectType class. I have fixed that please have a look


const graphql = require('graphql');   

const { GraphQLObjectType, GraphQLString, GraphQLSchema } = graphql;


const dummyData = [
    {name: 'Name of the Wind', genre: 'Fantasy', id:'1'},
    {name: 'The Final Empire', genre: 'Fantasy', id:'2'},
    {name: 'The Long Earth', genre: 'Sci-Fi', id:'3'}
];

const BookType = new GraphQLObjectType({
    name:'Book',
    fields: () => ({
        id: {type : GraphQLString},
        name: {type: GraphQLString},
        genre: {type: GraphQLString}
    })
});

const RootQuery = new GraphQLObjectType({
    name:'RootQueryType',
    fields: {
        book:{
            type:'BookType',
            args: {id:{type:GraphQLString}},
            resolve(parent,args) {
                return dummyData.find(book => book.id === args.id)
            }
        }
    }
});


module.exports = new GraphQLSchema({
    query:RootQuery
});

edited Jan 30, 2019 at 11:49

answered Jan 30, 2019 at 11:47

Mubeen Khan

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2 Comments

Boris Grunwald Over a year ago

Thank you very much, that was it.

Sandip Ghadge Over a year ago

type:'BookType' should be type: BookType

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