In many cases, it would be useful to convert an object to an array. We should add an aggregation expression to do so. For example, it could be called $objectToArray, and do something like this:
Currently, if a collection contains the following document:
There is no way to unwind that one document into the following three documents:
One way to accomplish this would be to add a stage to unwind documents, e.g.
Which would yield the following document, which could then be unwound to produce the desired result: