server.js

const express = require('express');
const bodyParser = require('body-parser');
const graphqlHttp = require('express-graphql');
const connectDB = require('./config/db')

// other imports
const schema = require('./graphql/schema/index');
const resolvers = require('./graphql/resolvers/index')

//Connect Database
connectDB();


// Create an express server and a GraphQL endpoint
const app = express();



app.use(bodyParser.json());

app.use((req, res, next) => {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'POST,GET,OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization');
    if (req.method === 'OPTIONS') {
      return res.sendStatus(200);
    }
    next();
  });

  
app.use('/graphql', graphqlHttp(
    {
        schema: schema,
        rootValue : resolvers,
        graphiql: true
    }
))


app.listen(4000, () => console.log('Express GraphQL Server Now Running On localhost:4000/graphql'));