nodemon - app crashed - waiting for file changes before starting - node.js

Question

I just started learning Node.js. The idea of this small application is to use express and mongosse to store some users in a based cloud database (mongoDB via mlab).
I have two seperate files :
User.js (models/User.js)
var mongoose = require('mongoose');
module.exports = mongoose.model('User', {
email : string ,
pwd : string
});
server.js (dossier root)
var express = require('express')
var cors = require('cors')
var bparser = require('body-parser')
var mongoose = require('mongoose')
var User = require('./models/User.js')
var app = express()
app.use(cors())
app.use(bparser.json())
app.post('/register', (req,res) => {
userData = req.body;
var user = new User(userData);
user.save((err, result) => {
if(err) console.log('IL YA UNE ERREUR')
result.sendStatus(200);
})
})
mongoose.connect('mongodb://user:pwd#ds261755.mlab.com:61755/myapp', { useMongoClient: true } , (erreur) => {
if(!erreur)
console.log('Connexion etablie');
})
app.listen(3000)
When I execute : nodemon server.js, I get the error below:
D:\Bureau\MEAN\appBackend\models\User.js:5
email : string ,
^
ReferenceError: string is not defined
at Object.<anonymous> (D:\Bureau\MEAN\appBackend\models\User.js:5:12)
at Module._compile (module.js:570:32)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
at Module.require (module.js:497:17)
at require (internal/module.js:20:19)
at Object.<anonymous> (D:\Bureau\MEAN\appBackend\server.js:6:12)
at Module._compile (module.js:570:32)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
at Module.runMain (module.js:604:10)
at run (bootstrap_node.js:389:7)
[nodemon] app crashed - waiting for file changes before starting...
Do you have any idea about this error?

Answer 1

Mongoose expects you to specify types using the built-in constructor functions, which are named with capital letters, e.g. String, Number, Boolean, etc.
var mongoose = require('mongoose');
module.exports = mongoose.model('User', {
email : String ,
pwd : String
});

Answer 2

define
module.exports = mongoose.model('User', new mongoose.Schema({
email : 'string' ,
pwd : 'string'
})
});
There is no string variable in the code .

Answer 3

this message will be appeared always when there's any small mistake.
I also faced this when module.exports type as module.export,just missed 's' only.

Answer 4

I come across with such error and on my case it was syntax error in the node js file.check your code for error as nodemon listen to change and run if no error there.
This was the error that make app-crashed ....
console.log("this is author",cope["author"];
SyntaxError: missing ) after argument list
at new Script (vm.js:79:7)
at createScript (vm.js:251:10)
at Object.runInThisContext (vm.js:303:10)
at Module._compile (internal/modules/cjs/loader.js:657:28)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
at Module.load (internal/modules/cjs/loader.js:599:32)
at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
at Function.Module._load (internal/modules/cjs/loader.js:530:3)
at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)
at startup (internal/bootstrap/node.js:283:19) After i correct the error [nodemon] restarting due to changes... [nodemon]
starting node server.js
That is it. Check for error in your code the nodemon automatically start the server.That is why nodemon is best rather than using node filename.js cz every time you have to start whenever you change the code.

Answer 5

The common reason is that you're trying to access the database from an IP that isn't whitelisted.
For my case, I was working on the same project on another PC. So, i had to whitelist the PC IP.
To do this, login to your cloud base mongodb, navigate to that your particular db project, and click on network access, add IP address and click on current ip address.
Also, make sure on your terminal, you run mongod to start your mongodb.
That solve for me

Answer 6

[nodemon] app crashed - waiting for file changes before starting...
You can fix this error with adding "start": "nodemon server.js" entry to your package.json file.

Answer 7

Test with this command:
npm install --save express-load

Answer 8

Many times we closed the PC and left the project running, when we used it again and ran the project again, that error appeared. I always solved it, restarting the pc. Everything worked perfectly.