Mongodb Search Query with Populate and regex - regex

Question

I want regex search on mongodb with NodeJS.
First One is Users and Second one is categories. Here I have saved categories id in Users
collection. I want a search Query that filter my records.
Users collection
{_id:'mongo_id', name:"User First",cat_id:2}
{_id:'mongo_id', name:"User Second",cat_id:2}
{_id:'mongo_id', name:"User Third",cat_id:1}
{_id:'mongo_id', name:"User Fourth",,cat_id:4}
Categories
Suppose id is numeric. For demo purpose I have written numeric values.
{_id:'1', name:"Salesman",}
{_id:'2', name:"Carpanter"}
{_id:'3', name:"Plumber"}
{_id:'4', name:"Engineer"}
I have a text input if I will type Carpanter or Carpan(regex) then I want 2 records, or
When I type User Second or second I want 1 Record
var query = {
'name': {
$regex: req.body.name,
$options: 'i'
}
};
innerQuery = {
path: 'category',
select: 'name'
}
Users.find(query)
.populate(innerQuery)
.sort({
'createdDate': -1
})

Answer 1

Your user record looks like this:
{_id:'mongo_id': name:"User First",cat_id:2}
I'll assume the extra : is a typo.
Aside from that, you are attempting to query for title. There is no path title in that record, so you can't query for it.
You're also trying to populate the path category, but there is no field with that name in the user records. The only related field I see is cat_id.
If you want to, for example, query by name and populate the cat_id, you can do something like this:
var query = {
'name': {
$regex: req.body.title,
$options: 'i'
}
};
var innerQuery = {
path: 'cat_id',
model: 'Category',
select: 'name'
};
This is entirely dependent on whether you named your model Category, and also what your schemas actually look like.
(PS, you're also trying to sort by createdDate, but I don't see that field in any of your records, either).