MongoDB, update collection field if new value is not null

Question

I would update a collection setting the value only if the new values are not null. I have a code like this:

 ...
 var userName = req.body.nome;
 var userSurn         


        

Answer 1

Probably you've got already user authenticated so you should have req.user.*

in this case you can use ternary operator to assign the value and update it with either new one or the current one (so there is no update)

var userName = req.body.nome ? req.body.nome : req.user.nome;
var userSurname = req.body.cognome ? req.body.nome : req.user.cognome;
var userAddress = req.body.indirizzo ? req.body.indirizzo : req.user.indirizzo;

collection.update(
     {_id:ObjectID(req.session.userID)},
     {$set: { nome: userName, cognome: userSurname, indirizzo: userAddress }}
)

If you don't have req.user then you can do it in 3 steps. 1. find user in collection 2. get current data 3. update data with new or current (as above)

let currentName
let currentSurname
db. collection.findOne({_id: ObjectID(req.session.userID)}, (err, user) => {
    if (err) { } // handle error here
    else if (user) {
        currentName = user.name
        currentSurname = user.surname
    }
})