Orders one array according to another array

order_by_array.rb

objects = []
order = %w(first second)

objects
  .group_by(&:order_by_this) # Create grouping according to field
  .each { |_, h| h.sort_by!(&:sort_each_by_this).reverse! } # Each hash sorted individually
  .values_at(*order) # Sorting according to order
  .compact # Reject empty hash keys (no elements for order item)
  .flatten(1) # Remove hash table
  .concat(objects.reject { |o| order.include? o.order_by_this }) # Append all unidentified at the end