Heroku failed to inject port number to process.env.PORT

Question

I'm deploying my server to Heroku, but for some reason the network shows it keeps making request still to the localhost, instead of dynamically injecting a port number to process.env.PORT

chrome console error message

This is the setup of my server.

 require('dotenv').config(); const express = require("express"); const graphqlHTTP = require("express-graphql"); const schema = require('./schema/schema'); const mongoose = require('mongoose'); const cors = require('cors'); const bodyParser = require('body-parser'); mongoose.connect(process.env.mongodburi, { useNewUrlParser: true }) mongoose.connection.once('open', ()=>{ console.log('Connected to database'); }); const app = express(); app.use(cors()); app.use(express.static("public")); app.use('/graphql', bodyParser.json(), graphqlHTTP({ schema, graphiql: true })); app.withCredentials = true; app.use('/', (req, res) => res.send("Welcome to read my profile")); const port = process.env.PORT; app.listen(port, ()=>{ console.log(`Now listening requests on port:${port}`); }) 

Answer 1

Use this

app.listen(process.env.PORT || 3000, function(){
    console.log("Express server listening on port %d in %s mode", this.address().port, app.settings.env);
});

Or run $ heroku config:set PORT=3333 as mentioned by ﾃﾞﾋﾞｯﾄ