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Class: RuboCop::Cop::Performance::DeleteSuffix

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, TargetRubyVersion, AutoCorrector, Base
Instance Chain:
self, ::RuboCop::Cop::RegexpMetacharacter, Base
Inherits: Base
  • Object
Defined in: lib/rubocop/cop/performance/delete_suffix.rb

Overview

In Ruby 2.5, String#delete_suffix has been added.

This cop identifies places where gsub(/suffix\z/, '') and sub(/suffix\z/, '') can be replaced by delete_suffix('suffix').

This cop has SafeMultiline configuration option that true by default because suffix$ is unsafe as it will behave incompatible with delete_suffix? for receiver is multiline string.

The delete_suffix('suffix') method is faster than gsub(/suffix\z/, '').

Examples:

# bad
str.gsub(/suffix\z/, '')
str.gsub!(/suffix\z/, '')

str.sub(/suffix\z/, '')
str.sub!(/suffix\z/, '')

# good
str.delete_suffix('suffix')
str.delete_suffix!('suffix')

SafeMultiline: true (default)

# good
str.gsub(/suffix$/, '')
str.gsub!(/suffix$/, '')
str.sub(/suffix$/, '')
str.sub!(/suffix$/, '')

SafeMultiline: false

# bad
str.gsub(/suffix$/, '')
str.gsub!(/suffix$/, '')
str.sub(/suffix$/, '')
str.sub!(/suffix$/, '')

Cop Safety Information:

  • This cop is unsafe because Pathname has sub but not delete_suffix.

Constant Summary

Instance Attribute Summary

::RuboCop::Cop::RegexpMetacharacter - Included

#safe_multiline?

Instance Method Summary

::RuboCop::Cop::RegexpMetacharacter - Included

#drop_end_metacharacter, #drop_start_metacharacter, #literal_at_end?, #literal_at_end_with_backslash_z?, #literal_at_end_with_dollar?, #literal_at_start?, #literal_at_start_with_backslash_a?, #literal_at_start_with_caret?

Instance Method Details

#on_csend(node)

Alias for #on_send.

[ GitHub ] 

  


# File 'lib/rubocop/cop/performance/delete_suffix.rb', line 90



alias on_csend on_send


  








  

    #on_send(node)  
    Also known as: #on_csend
  

  [ GitHub ]


  

  


# File 'lib/rubocop/cop/performance/delete_suffix.rb', line 71



def on_send(node)
  return unless (receiver, bad_method, regexp_str, replace_string = delete_suffix_candidate?(node))
  return unless replace_string.empty?

  good_method = PREFERRED_METHODS[bad_method]

  message = format(MSG, current: bad_method, prefer: good_method)

  add_offense(node.loc.selector, message: message) do |corrector|
    regexp_str = drop_end_metacharacter(regexp_str)
    regexp_str = interpret_string_escapes(regexp_str)
    string_literal = to_string_literal(regexp_str)

    new_code = "#{receiver.source}#{node.loc.dot.source}#{good_method}(#{string_literal})"

    corrector.replace(node, new_code)
  end
end