UnhandledPromiseRejectionWarning: ValidationError

Question

I'm running into a trouble since a few days. I'm learning the MEAN stack, but during creation of a user on mongo using mongoose schema, I have this problem :

(node:93337) UnhandledPromiseRejectionWarning: ValidationError: User validation failed: username: Path username is required., password: Path password is required., email: Path email is required.

Here's my code :

The server part :

mongoose.connect('mongodb://localhost:27017/Wisebatt', err => {
  if (err) {
    console.log(`Not connected to db ${err}`)
  } else {
    console.log('Successfully connected to db')
  }
})

...

app.post('/register', (req, res) => {
    const user = new User();
    user.username = req.body.username;
    user.password = req.body.password;
    user.email = req.body.email;
    user.save();
    res.send('User created');
});

The UserSchema :

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const UserSchema = new Schema({
    username: { type: String, required: true, unique: true},
    password: { type: String, required: true },
    email: { type: String, required: true, unique: true},
});

module.exports = mongoose.model('User', UserSchema);

Here are the add-ons I'm using :

• Express,
• Nodemon,
• Morgan,
• Body Parser,
• Mongo (With mongod running & Mongoose)

Answer 1

try adding this to your express code prior to your routes. This is a middleware that will setup the req.body object when you send requests to the backend. (you'll also need to npm install --save body-parser)

const bodyParser = require('body-parser')
app.use(bodyParser.urlencoded({ extended: true }))
app.use(bodyParser.json())

if youre using a rest client. make sure that you have a request header such as:

Content-Type: application/x-www-form-urlencoded

Answer 2

Okay I found the problem...

Clearly, the problem is due to one of these two :

• The browser used,
• The extension sending the POST request

Surprise, I tried with Postman, and the request successfully work. So all the code was great, the problem came from one of the two up.

So, that learned me a thing. If it's not your code, It's the software you're using that can destroy all you have done

Answer 3

If you are using expressJS then make sure that you have to add this lines.

const express = require('express');
const app = express();
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

Specially this one,

app.use(express.urlencoded({ extended: true }));

This actually solved my problem.

Answer 4

Use:

app.use(express.urlencoded({ extended: true })); // this is for app.post to submit route.. 

in the app.js or index.js