How to update a field using its previous value in MongoDB/Mongoose [duplicate] - mongodb

Question

This question already has answers here:
Update MongoDB field using value of another field
(12 answers)
Closed 5 years ago.
I know I can do an update using $set:
Contact.update({
_id: request.id
}, {
$set: { name: newNameValue }
}, {
upsert: false
}, function(err) { ... });
But in this case, instead of passing newNameValue, I'd like to use the previous name value to compute the new one. Let's say I want to capitalize the old name, something like:
Contact.update({
_id: request.id
}, {
$set: { name: $old.name.toUpperCase() }
}, {
upsert: false
}, function(err) { ... });

Answer 1

I think this has already been answered here: How to add new data to current string in MongoDB?, so please, check that for a more detailed answer, but anyway, in short, you can't do that with a single query.
The way to do it using Mongoose, as shown in this official Mongoose example:
Contact.findById(request.id, (err, contract) => {
if (err) return handleError(err);
contract.name = contract.name.toUpperCase();
contract.save((err, contractContract) => {
if (err) return handleError(err);
...
});
});

Answer 2

as far as I know it's not possible. You would need to find and then update
Contact
.find({
_id: request.id
})
.exec(function(err, data) {
if (err) {
return ...;
}
Contact.findByIdAndUpdate(request.id, {
$set: {
name: data.name.toUpperCase()
}
}, {
new: true
}, function(err, doc) {
if (err) return ...;
console.log(doc)
});
}