Mongoose - function inside .find method does not pass result - node.js

Question

How do I pass the result of the function successfully into .find method ? I want the argument passed via body-parser to be used as value for the key 'name' if user submitted a non-empty string. If user submitted an empty string, then empty object should be passed into .find method.
Function console.log works. If I submit an empty string then 'empty querydb' is printed to the console. Likewise, if I submit any other string then it gets printed out to the console correctly.
How can I pass the req.body.querydb as a value to 'name' key ?
HTML
<form method="POST" action="form_query">
<input type="textarea" name="querydb">
<br><br>
<button> Query </button>
</form>
.JS
router.post('/form_query', function(req,res) {
someModel.find(function(err,results){
if(!req.body.querydb){
console.log("empty querydb")
return {}
} else {
console.log(req.body.querydb)
return {name:req.body.querydb}
}
}).exec(function(err, result) {
if (err) {
send(err)
} else {
console.log('omg')
}
Much thanks !

Answer 1

In mongoose you have two possibilities to make a find request
the find(query, callback) function
the query builder
I recommand you to use the find() function. In your case, your code is like more this :
router.post('/form_query', function(req,res, next) {
someModel.find({
name : req.body.querydb
}, function (err, users) {
if (err) {
// request has an error like connection problem
res({ error : err });
return;
}
// request works correctly, you can send the users array for example
res(users);
});
});
The find function works like the mongodb pure find() function and, for me, it's the best way to make your requests.
EDIT :
It is advisable to control the incoming variables in the best way to perform this find.
For example, You can make this :
let findQuery = {};
if (req.body.querydb) {
findQuery.name = req.body.querydb
}
someModel.find(findQuery, function (err, users) {
// ...
});

Answer 2

I am not really sure what you are looking for but trying to understand as much as possible i am giving some code. This way you pass req.body.querydb as a value to 'name' key.
router.post('/form_query', function(req,res) {
someModel.find({name:req.body.querydb},function(err,results){
if(!req.body.querydb){
console.log("empty querydb")
return {}
} else {
console.log(req.body.querydb)
return {name:req.body.querydb}
}
}).exec(function(err, result) {
if (err) {
send(err)
} else {
console.log('omg')
}

Answer 3

From what I can tell you are looking to pass a value from the api into a mongo query.
It might make sense to define the query outside of the actual call and then build it as needed or to ensure that a value is passed before getting to the query.
For example:
router.post('/form_query', function(req,res) {
if(!req.body.querydb) {
return res.status(404).send("empty querydb");
}
// validate querydb param
someModel.find({ name: req.body.querydb }, function(err,results){
if(!req.body.querydb){
console.log("empty querydb")
res.send
} else {
console.log(req.body.querydb)
return res.status(200).send(results);
}
})
});
If you are using mongoose then the callback will be called after execution, and the query is the first param passed into the .find function.