why mongoose queries dos not work when put inside promise function - node.js

Question

My code is as shown below:
checkAndCreateUser(customer_id, email_id).then(result => {
console.log("result is " + result);
});
var checkAndCreateUser = function (custom_id, email) {
return new Promise(function (resolve, reject) {
if ((!custom_id) && (custom_id.trim() == '')) {
var creatUser = new user();
// creatUser._id = user_id;
creatUser.ph_no = ph_no;
creatUser.email_id = email;
console.log("fn works");
user.findOne({
'email_id': email
}, function (err, user) {
console.log("db test");
if (!user) {
creatUser.save(function (err, userInfo) {
if (err) {
reject("no id found");
} else {
customer_id = userInfo._id;
resolve(customer_id);
}
});
} else {
customer_id = user._id;
resolve(customer_id);
}
});
}
});
}
Now what happens here is I am not able to successfully run db query. I am able to get console.log("fn works") printed , but it does not print console.log("db test"). So what exactly is going wrong?

Answer 1

You forgot save your user, besides Mongoose already returned promise, you don't need use callbacks:
var checkAndCreateUser = function (custom_id, email) {
return User.create({ ph_no :ph_no,
email_id :email})
.then(result=>{
return User.findOne({'email_id': email})
})
.then(user=>{
return user._id;
})
};
As for mistake in your function:
...
let user = new User({email_id: email, ph_no: phone});
user.save();//you forgot about this
...
You can use save() with callback:
user.save((err, result)=>{...});
Or with promise:
user.save().then(result=>{...}).catch(err=>{...});