Currently, I am developing a user authentication backend using express and mongoose.
My main focus right now is enabling users to update their name and email address.
To achieve this, I am implementing a system where the email input is cross-checked with the current user's email. If it doesn't match, then I verify if it matches any other user's email. If there is a match with another user, an error is thrown; otherwise, the new email is saved.
The process works smoothly for updating names and emails, except when a user already has the chosen username.
Upon encountering an error, both the error message is sent to the client and the server crashes with an "ERR_HTTP_HEADERS_SENT" error. Despite returning the error, I am unable to identify the root cause of this issue.
Below is the code snippet:
exports.update = (req, res) => {
// Obtain New User Details
const { firstName, lastName, email } = req.body;
// Locate User
User.findById(req.user._id, (err, user) => {
if (err || !user) {
return res.status(400).json({
error: 'User not found.'
});
}
user.firstName = firstName;
user.lastName = lastName;
// Check for Duplicate Email
if (email !== user.email) {
User.findOne({ email: email }).exec((err, existingUser) => {
// Display Error Message if Duplicate Found
if (!err && existingUser) {
return res.status(400).json({
error: "This email address is already in use.",
});
}
// Send alert email to old address if no duplicate found.
});
// Update Email Address
user.email = email;
}
// Save Updated User Information
user.save((err, updatedUser) => {
if (err) {
console.log("Error: Could not update user.");
return res.status(400).json({
error: 'User update failed.'
});
}
updatedUser.hashedPassword = undefined;
updatedUser.salt = undefined;
return res.json({
message: 'Account updated successfully.',
data: updatedUser
});
});
});
};