combine 2 objects and sort rails 5

Question

I want to show a time link mixing comments and post so I have this objects

@posts = Post::all()
@comments = Comment::all()

If I do this

Answer 1

Posts and comments are different models (and different tables), so we can't write SQL to get sorted collection, with pagination etc.

Usually I use next approach when I need mixed timeline.

I have TimelineItem model with source_id, source_type and timeline_at fields.

class TimelineItem < ApplicationRecord
  belongs_to :source, polymorphic: true
end

Then I add in models logic to create timeline_item instance when needed:

has_many :timeline_items, as: :source
after_create :add_to_timeline

def add_to_timeline
  timeline_items.create timeline_at: created_at
end

Then search and output as simple as

TimelineItem.includes(:source).order(:timeline_at).each { |t| pp t.source }