Updating mongoose schema fields concurrently - node.js

Question

I'm trying to update a mongoose schema. Basically I have two api's '/follow/:user_id' and '/unfollow/:user_id'. What I'm trying to achieve is whenever user A follows user B , user B followers field in mongoose will increment as one.
As for now I managed to get only following fields increment by one but not the followers fields.
schema.js
var UserSchema = new Schema({
name: String,
username: { type: String, required: true, index: { unique: true }},
password: { type: String, required: true, select: false },
followers: [{ type: Schema.Types.ObjectId, ref: 'User'}],
following: [{ type: Schema.Types.ObjectId, ref: 'User'}],
followersCount: Number,
followingCount: Number
});
Updated version: I tried my solution, but whenever I post it, it just fetching the data ( I tried the api's on POSTMAN chrome app ).
api.js
// follow a user
apiRouter.post('/follow/:user_id', function(req, res) {
// find a current user that has logged in
User.update(
{
_id: req.decoded.id,
following: { $ne: req.params.user_id }
},
{
$push: { following: req.params.user_id},
$inc: { followingCount: 1}
},
function(err) {
if (err) {
res.send(err);
return;
}
User.update(
{
_id: req.params.user_id,
followers: { $ne: req.decoded.id }
},
{
$push: { followers: req.decoded.id },
$inc: { followersCount: 1}
}
), function(err) {
if(err) return res.send(err);
res.json({ message: "Successfully Followed!" });
}
});
});
These codes only manage to increment the user's following fields, and without duplication. How do I update logged in user's following fields and as well as other user's followers fields at the same time?
Updated version: it keeps fetching the data.

Answer 1

May be this is how you want to. Instead of using update, you can also use findOneAndUpdate from Mongoose queries.
apiRouter.post('/follow/:user_id', function(req, res) {
User.findOneAndUpdate(
{
_id: req.decoded.id
},
{
$push: {following: req.params.user_id},
$inc: {followingCount: 1}
},
function (err, user) {
if (err)
res.send(err);
User.findOneAndUpdate(
{
_id: req.params.user_id
},
{
$push: {followers: req.decoded.id},
$inc: {followersCount: 1}
},
function (err, anotherUser) {
if (err)
res.send(err);
res.json({message: "Successfully Followed!"})
});
});
}
If you are not sure about it is updated or not, you can just use console.log() for both user and anotherUser variables to see changes.