Migration Guides - Mongoose 3.x to 4.x - 《Mongoose v6.0 Documentation》

Mongoose’s findOneAndUpdate(), findOneAndRemove(), findByIdAndUpdate(), and findByIdAndRemove() functions are just wrappers around MongoDB’s . Both the MongoDB server and the MongoDB NodeJS driver set the new option to false by default, but mongoose 3 overwrote this default. In order to be more consistent with the MongoDB server’s documentation, mongoose will use false by default. That is, findOneAndUpdate({}, { $set: { test: 1 } }, callback); will return the document as it was before the $set operation was applied.

In Mongoose 3, CastError and ValidationError had a type field. For instance, user defined validation errors would have a type property that contained the string ‘user defined’. In Mongoose 4, this property has been renamed to kind due to the V8 JavaScript engine using the Error.type property internally.