An example of using the Decorator pattern for filtering out profanity

clean_post.rb

class CleanPost < SimpleDelegator
  def title
    # calling `super` here will return the value of the #title from the original object
    Profanity.filter(super)
  end
end

# usage
unclean_post = Post.new(title: "foo BAD WORD bar")
unclean_post.title # => "foo BAD WORD bar"

clean_post = CleanPost.new(unclean_post)
clean_post.title # => "foo *** *** bar"

A "Decorator" is an object which takes in another object and extends / alters / "decorates" that object's data.

In this example, we create a decorator called CleanPost which takes in a regular Post and overrides it's title method to be filtered. This is all facilitated by Ruby's built-in SimpleDelegator object.

Here's a good resource for learning more about using it:
https://blog.encoredevlabs.com/feature/ruby/decorator/simpledelegator/2017/01/20/easy-decorating-in-ruby.html