Express-validation not producing the correct errors - node.js

Question

So, this worked before, and all the sudden decided to stop working, and I have no idea why.
EDIT: Updated the code to show what I currently got now
router.post('/register', async (req, res) => {
// let query
let query;
// Start email checks
req.check('email', 'Email is not valid.')
.isEmail()
.custom(async value => {
query = {email: value};
User.findOne(query).then(user => {
if (user) return false;
});
}).withMessage('Email is in use.');
// Start username checks
req.check('username', 'Username is required.')
.notEmpty()
.isLength({ min: 5, max: 15}).withMessage('Username requires 5-15 alphanumberic characters.')
.isAlphanumeric().withMessage('Username must be alphanumeric only.')
.custom(async value => {
query = {username: value}
User.findOne(query).then(user => {
if (user) return false;
});
}).withMessage('Username is in use.');
// Start password checks
req.check('password', 'Password is required.')
.notEmpty()
.isLength({min: 5}).withMessage('Password must be atleast 5 characters long.');
req.check('confirmPassword', 'Confirm Password is required.')
.notEmpty()
.custom(value => value === req.body.password).withMessage('Password must match');
const errors = await req.getValidationResult();
//console.log(errors);
if (!errors.isEmpty()) {
res.render('index', {
errors: errors.mapped()
});
} else {
let newUser = new User({
email: req.body.email,
username: req.body.username,
password: req.body.password,
});
let hash = bcrypt.hashSync(req.body.password, 10);
newUser.password = hash;
newUser.save(err => {
if (err) {
console.log(err);
} else {
res.render('index', {
success: 'Registration Successful'
});
}
});
}
});
So its pretty clear its something with my custom checks, and I do not know why.
EDIT:
It seems there is confusion. The checks are working correctly, what I'm having issues with is it populating the errors when I want it to. If i try to register with the same email, it will pull up the user and will go through my if statements. If I use Promise.reject() it doesn't work. If I use false, it doesn't work. Again, the checks itself work, the error handling seems like it isn't.
EDIT TWO:
So I have tried this method (all the other code is still the same)
// Start email checks
req.checkBody('email', 'Email is not valid.')
.isEmail()
.custom(value => {
query = {email: value}
User.findOne(query).then(user => {
if (user) console.log('Email Exists'); return false;
});
}).withMessage('Email in use.');
// Start username checks
req.check('username', 'Username is required.')
.notEmpty()
.isLength({ min: 5, max: 15}).withMessage('Username requires 5-15 alphanumberic characters.')
.isAlphanumeric().withMessage('Username must be alphanumeric only.')
.custom(value => {
query = {username: value}
User.findOne(query).then(user => {
if (user) console.log('Username Exists'); return false;
});
}).withMessage('Username in use.');

Answer 1

This should work. Since node.js is non render blocking,the db query may not complete before it proceeds to next step. You could use the format I have posted below or try the async library in which case await keyword should be placed before User.findOne
User.findOne(query).then(user=>{
if(user) return false
}).catch(err => console.log(err))

Answer 2

Finally found an answer, which incidentally makes it a little easier to read as well. I ended up making my own custom validators:
customValidators: {
emailExists: (email) => {
let query = {email: email};
return new Promise((resolve, reject) => {
User.findOne(query, (err, results) => {
if (results === null) {
resolve(err);
}
reject(results);
});
});
},
userNameExists: (username) => {
let query = {username: username};
return new Promise((resolve, reject) => {
User.findOne(query, (err, results) => {
if (results === null) {
resolve(err);
}
reject(results);
});
});
}
},
Then:
req.check('email', 'This email is in use.').emailExists();
req.check('username', 'Username is in use.').userNameExists();
req.asyncValidationErrors().then(() => {
console.log('No errors');
let newUser = new User({
email: req.body.email,
username: req.body.username,
password: req.body.password,
});
let hash = bcrypt.hashSync(req.body.password, 10);
newUser.password = hash;
newUser.save(err => {
if (err) {
console.log(err);
} else {
res.render('index', {
success: 'Registration Successful'
});
}
});
}).catch(errors => {
res.render('index', {
errors: errors
});
});