The ancestry gem has a lot of methods to navigate the tree structure. You can do Model.roots to show all root elements etc. How do opposite? - return newest child for each tree structure.
I thought about adding an extra column to my model (latest/boolean) and then do some logic with after save filters etc. However this feels a bit clumsy. :/
Best regards. Asbjørn Morell
Old question, still relevant. Found myself a solution (bit clumsy as well) but I think it works fairly well.
Extend the Array class with a method like this:
class Array
def ancestry_last_child
last_child = self.map { |a| [a[:id], a[:ancestry], a[:updated_at]] }.sort_by { |id, anc, dat| [anc.split('/').length, dat] }.last
self.find { |a| a[:id] == last_child[0] }
end
end
After that just use it (with preceding validation) like this:
account = Account.find([id])
if account.has_children?
last_child = account.descendants.ancestry_last_child
end
if you have doubts about extending ruby/rails core classes this will help
::EDIT::
previous solution didn't work in full. This solution requires an updated_at and id column
Maybe you can hack something together with the Class#inherited hook, like updating an attribute of the parent model on creation of the new subclass:
