UnhandledPromiseRejectionWarning: Unhandled promis

Question

I have an app developed using MEAN stack. I am getting the following error

(node:4920) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): MongoError: failed to connect to server [ds047865.mongolab.com:47865] on first connect [Mon goError: connect ECONNREFUSED 130.211.211.211:47865]

(node:4920) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code

here is my code:

    var mongoose = require('mongoose');
var validator = require('mongoose-unique-validator'); 
var nodemailer = require('nodemailer');
mongoose.connect('mongodb://naresh:[e-mail]:49025/languageapp', { useMongoClient: true });  
var db = mongoose.connection;
db.on('connect', function () { console.log('connected'); });


var userSchema = new mongoose.Schema({
    userName: { type: String, required: true, index: true, unique: true },
    userEmail: { type: String, required: true, index: true, unique: true },
    userPass: { type: String, required: true },
    Date: { type: String, default: Date.now() },
    userResult: String
});
var questionSchema = new mongoose.Schema({
    question: { type: String, unique: true },
    op1: String,
    op2: String,
    op3: String,
    op4: String,
    rightAnswer: String,
    questionType: String,
    questionID: String,
    quizTopic: String,
    CreatedAt: { type: String, default: Date.now() }
});
var resultSchema = new mongoose.Schema({
    userID: String,
    userName: String,
    userMatriculation: String,
    userEmail: String,
    quizTopic: String,
    userResult: String,
    date: { type: String, default: Date.now() }
});
userSchema.plugin(validator);
var User = mongoose.model('Users', userSchema);
var Question = mongoose.model('Questions', questionSchema);
var Result = mongoose.model('Results', resultSchema);

I am not using any promises though am getting these errors.

Answer 1

According to your connection string 'mongodb://naresh:[e-mail]:49025/languageapp', the dbuser is naresh and the dbpassword is also naresh. So you have to make sure that you have already created (explicitly) a database user (dbuser) with that same credential. This is NOT the same credential that you use to logon to mlab.com.

To create the database user, go to the Users lab in the mlab.com portal and click on "Add database user".