It is very easy as a developer to make the mistake of thinking documentation for the MongoDB shell applies to the node driver because many methods are so similar between the two.

Imagine my surprise and confusion on finding that returnNewDocument doesn't work in the node driver, and I have to use returnOriginal instead, which takes the opposite value.

I think most developers would try to minimize mismatch between the node API/shell if they could start from scratch. Consistency in naming helps everyone.