Dynamic query order scopes in Rails

One of my favourite query scopes in Laravel is latest() which will order the query by the latest models based on the created_at column. In addition you can pass the column you want to order on in case you need something else.

I wanted to implement this in Rails but couldn't work out how to use a symbol as a column name for the column_name: :sort_direction syntax, but soon realised I could use the hashrocket to get it to work the way I wanted.

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true

  scope :latest, ->(column = :created_at) { order(column => :desc) }
end

With this code in your base record model you can easily query your database by a given column. Be careful to consider indexing columns when this is necessary.

# Latest created posts.
Post.latest

# Latest published posts.
Post.latest(:published_at)