class << self vs self.method with Ruby: what's better?
ruby
Solution
`class << self` is good at keeping all of your class methods in the same block. If methods are being added in `def self.method` form then there's no guarantee (other than convention and wishful thinking) that there won't be an extra class method tucked away later in the file.
`def self.method` is good at explicitly stating that a method is a class method, whereas with `class << self` you have to go and find the container yourself.
Which of these is more important to you is a subjective decision, and also depends on things like how many other people are working on the code and what their preferences are.
Problem
This Ruby Style Guide tells that is better using `self.method_name` instead of `class method_name`. But Why? ``` class TestClass # bad class << self def first_method # body omitted end def second_method_etc # body omitted end end # good def self.first_method # body omitted end def self.second_method_etc # body omitted end end ``` Are there performance issues?