class << self vs self.method with Ruby: what's better?

Question

This Ruby Style Guide tells that is better using self.method_name instead of class method_name. But Why?

class TestClass
  # bad
           


        

Answer 1

Whichever you want. Both are very clear for what you do. But I think of some recommendations for this.

When there're only one class method to define, Use def self.xxx. Because for defining only one method, increasing indent level probably become cluttering.

When there're more than one class method to define, Use class << self. Because writing def self.xxx, def self.yyy and def self.zzz is certainly repetition. Create a section for these methods.

When all methods in a class are class method, you can use module with module_function instead of class. This let you define module functions just use def xxx.