Question

I have a document structure in MongoDB like this:

User
 |---> Posts
        |----> Comments

So, a parent document User with a collection of embedded Post documents, which itself has a collection of embedded Comment documents.

I grab the User document back and now have the entire document tree in memory, like so:

user = User.where(username: 'test').first

From user how can I get a list of all the comments?

Answer 1

Try something like this:

user.posts.map{|p| p.comments}.flatten

Or

user.posts.flat_map(&:comments)