Confusion due to (proposed) spread operator on model instance

See https://github.com/sebmarkbage/ecmascript-rest-spread for a description of the spread operator. It behaves much like Object.assign() and it iterates over the object’s own properties.

When I use {...obj} on model instance, I don’t get a copy of the plain object as I expected but instead a copy of all the mongoose internals.

So basically, it would be nice if that either worked, or if, in development at least, iterating over own properties would throw.

[vkarpov15]

You can’t. The spread operator always creates a new object, so you can’t use it to update an existing object. Use Object.assign() as an alternative. Or, better yet, just use card.set(cardData), see Document#set()

[vkarpov15]

By design. Use doc.toObject() on the rhs of the spread operator. A mongoose doc doesn’t really lend itself well to copying, too much syntactic sugar for change detection