fetch data from couchdb to node.js file

Question

hi everyone i have a probleme whene i want to fetch data from couchdb to file .ejs i have this probleme "Server started on 3000 Port undefined"

this is my code

const express = require('express');  
const bodyParser = require('body-parser');  
const path = require('path');  
const NodeCouchdb = require('node-couchdb');  

 
const couch =new NodeCouchdb({  
auth:{  
user: 'admin'  ,
password: 'admin'  
}  
});  

const dbName = "mydata";

const viewUrl = "_design/_allproducts/_view/all";


couch.listDatabases().then(function(dbs){  
console.log(dbs);  
});  
 
const app = express();  
app.set('view engine', 'ejs');  
app.set('views', path.join(__dirname, 'views'));  
app.use (bodyParser.json());  
app.use(bodyParser.urlencoded({extended: false}));  
app.get('/', function(req,res){  
    couch.get(dbName, viewUrl).then(function(data, headers, status){
                 console.log(data);
                 res.render('views',{mydata:data})
    },
    function(err){

        res.send(err);
    });
});  
app.listen(3000, function(){  
 console.log('Server started on 3000 Port');  
})

i try to chenge something on congiration file of couchdb couchdb.init but it's not working