Why are Mongoose documents not plain JavaScript objects by default?

Question

When returning Mongoose documents from a MongoDB database, you can't just edit the returned document. You either need to convert it to a plain JavaScript object by the .toObject() function - which has yet to work for me - or JSON.parse(JSON.stringify(doc)) it.

My question is why is this the case? Why aren't they just returned as plain, simple, easy to use JavaScript objects by default?

Answer 1

Because Mongoose documents have additional functionality, like various built-in and custom instance methods . It allows you to call document.save(...) after changing a document, for instance.

If you want your queries to return plain objects, you can also use the lean option.