new object returns as empty object in expressjs post request

Question

This problem is driving me crazy.

The purpose of this route is to create or login users, I have created new user successfully but I am having trouble sending objects as a response but all it comes is empty object.

I tried console.log() a new error that i intentionally created but it does not show up in console either

Here is the app setup

// middleware setup
app.use(cors());
app.use(express.urlencoded({extended: true}));
app.use(express.json());
app.use('/', usersRoute);

my code is like this its not the full code but it shows a place where the code fails

router.post('/register', async (req, res) => {

const enteredUser = req.body;

// Validate entered user information
const { error } = validateUser(enteredUser);
if (error) return res.status(400).send(error);

try {

    // Make sure user does not exist
    const isAlreadyUser = await User.findOne({ 
        username: enteredUser.username
    });
    if (isAlreadyUser) {
        const err = new Error('already user');
        return res.status(201).send({
            isAlreadyUser,
            err
        });
    }

// Hash the password
    const salt = await bcrypt.genSalt(10);
    const hashed = await bcrypt.hash(enteredUser.password, salt);

    console.log(salt, hashed);

    // Create new model instance
    const newUser = new User({
        username: enteredUser.username,
        password: hashed,
        isCustomer: enteredUser.isCustomer
    });

    // Save new user to db
    await newUser.save();

    // generate token
    const token = newUser.genToken();

    console.log(token);

    // send token to front-end
    return res.status(200).send(token);

} catch (error) {

    return res.status(400).send(error);
}
})

the response will be like this

{
    "isAlreadyUser": {
        "isCustomer": true,
        "_id": "5fb0df0c7f3bb4069ed32615",
        "username": "Raffi2",
        "password": "$2b$10$tlHJGtax75mR4L3gG.cJhuIfy/t7IEKX4n49kIElZ41k7jZAe/2rO",
        "__v": 0
    },
    "err": {}
}

the problem happens with couple object types like Error and jsonwebtoke

can anyone help ?

Okay, thank you. What is the output of the console.log(token)? Is it defined? — Wasbeer, Nov 15 '20 at 08:37
the thing is the console shows nothing it does not even say defined or undefined — Raffi, Nov 15 '20 at 08:38
Okay. Are you sure you are doing a request to this particular route? — Wasbeer, Nov 15 '20 at 08:39
100 percent as there are no other routes for now this is the only one — Raffi, Nov 15 '20 at 08:40
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/224578/discussion-between-wasbeer-and-raffi). — Wasbeer, Nov 15 '20 at 08:41
thanks mate appreciate it, also the other object "token" was undefined as I used this in getToken which is arrow function. reverted to normal function, now issue is completely resolved. :) — Raffi, Nov 15 '20 at 10:26

Wasbeer · Accepted Answer · 2020-11-15T09:59:04.683

1

The res.status(201).send call will return an empty object in the property err because the properties of the returned object of new Error('already user') are not enumerable and the response is JSON.stringified.

Reference:

edited Nov 15 '20 at 09:59

answered Nov 15 '20 at 09:49

Wasbeer

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new object returns as empty object in expressjs post request

1 Answers1