Very similar Node routes - any better solution? - node.js

Question

I have two very similar routes (two API results). So one for grabbing the email address and one for grabbing their username. I'm using these two separately, one for validating the email address by using an AJAX call and another for validating the username (basically checking if either exist).
Is there any way in Node/Express/Mongoose to specifically check both (at seperate times) without having to have two methods, it just feels so redundant?
Used to check for email validation (that it doesn't already exist)
router.get('/:id', function(req, res) {
var emailAddress = req.params.id;
User.find({ 'emailAddress': emailAddress }, function (err, user) {
if(!user) {
res.statusCode = 404;
return res.json({
error: 'Not found'
});
}
if (!err) {
if (user[0]!=undefined) {
return res.json(true);
} else {
return res.json({
error: 'Not found'
});
}
} else {
res.statusCode = 500;
log.error('Internal error(%d): %s', res.statusCode, err.message);
return res.json({
error: 'Server error'
});
}
});
});
Used to check for username validation (that it doesn't already exist)
router.get('/username/:id', function(req, res) {
var username = req.params.id;
User.find({ 'username': username }, function (err, user) {
if(!user) {
res.statusCode = 404;
return res.json({
error: 'Not found'
});
}
if (!err) {
if (user[0]!=undefined) {
return res.json(true);
} else {
return res.json({
error: 'Not found'
});
}
} else {
res.statusCode = 500;
log.error('Internal error(%d): %s', res.statusCode, err.message);
return res.json({
error: 'Server error'
});
}
});
});
Just returning boolean's essentially for both results. Surely there's a better way than this? There's just so much duplicated code it's frustrating.
Edit: still researching but maybe I could use User.find() and pass in what I want but in terms of passing that from the API to the user Model, how is that possible?

Answer 1

Split them in to reusable units and use them in the routes.
function isUserExists(query, callback) {
User.findOne(query, function(error, user) {
if(error) {
return callback(error);
}
callback(null, !!user);
});
}
function sendResponse(res, error, result) {
if(error) {
res.statusCode = 500;
log.error('Internal error(%d): %s', res.statusCode, err.message);
return res.json({error: 'Server error'});
}
if(!user) {
res.statusCode = 404;
return res.json({
error: 'Not found'
});
}
res.json(result);
}
router.get('/:id', function(req, res) {
isUserExists({emailAddress: req.params.id}, sendResponse.bind(null, res));
});
router.get('/username/:id', function(req, res) {
isUserExists({username: req.params.id}, sendResponse.bind(null, res));
});