Efficient way to check if username/email already exist in MongoDB for registration

Question

I'm in a NodeJS server using ExpressJS to handle my /register route. One step in my registration process is to ensure that the user's username and email are both unique, if so, they can register and add their account to the users collection.

Currently, my code is as follows for this "checking if username/email exists" step:

// Checking is user already exists (username & email)
try {
    const usernameExists = await User.findOne({username: req.body.username});
    const emailExists = await User.findOne({email: req.body.email});
    if (usernameExists && emailExists) return res.status(400).send("Username and email already taken");
    if (emailExists) return res.status(400).send("Email already taken");
    if (usernameExists) return res.status(400).send("Username already taken");
} catch (e) {
    return res.status(500).send("Error querying DB to check if username/email exists or not");
}

This feels highly inefficient as I'm doing two queries to the database. Is there anyway to combine the two User.findOne... queries? Or is this how this task is supposed to be done?

Thanks so much!

Answer 1

You can check for unique values in schema itself, just add unique in schema for the field you want. Like this

email:{
   unique:true,
   required:true,
},
username:{
   unique:true,
   required:true,
}

Answer 2

You could use $or

await User.findOne({
  $or: [{ username: req.body.username }, { email: req.body.email }],
})