Mongoose findOneAndUpdate Upsert _id null?

Question

I\'d like to have a single method that either creates or updates a document for a policy. Searching and trying different techniques like this one, I have come up with a nul

Answer 1

I am not using Mongoose, but I run into similar issue with MongoDB. For Upsert action when new object was inserted the MongoDB was setting null to _id.

I was calling:

findOneAndUpdate({my_id:'my_unique_id'}, obj, {upsert: true})

where obj._id was undefined.

The problem was that _id was present on list of keys Object.keys(obj). I found that I was assigning obj._id = some_variable, where some_variable was undefined, and that was causing _id to appear on a list of keys.

I applied workaround by calling right before upsert:

if (_.isUndefined(obj._id)) {
  delete obj._id;
}