JAVASCRIPT

mongoose save or update

// This will create another document if it doesn't exist
findByIdAndUpdate(_id, { something: 'updated' }, { upsert: true });

Update data using mongoose

const res = await Person.updateOne({ name: 'Jean-Luc Picard' }, { ship: 'USS Enterprise' });
res.n; // Number of documents matched
res.nModified; // Number of documents modified

save or update mongoose

// SAVE NEW OR UPDATE EXISTING COLLECTION
AnnoucementTagsModel.findOneAndUpdate({_id: announcementId}, newAnnoucementTags, {upsert: true}, function (err, doc) {
	if (error) throw new Error(error);
	console.log("succesfully saved");
});