Class: RuboCop::Cop::Performance::Casecmp

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/performance/casecmp.rb

Overview

Identifies places where a case-insensitive string comparison can better be implemented using ‘casecmp`.

This cop is disabled by default because ‘String#casecmp` only works with ASCII characters. See github.com/rubocop/rubocop/issues/9753.

If you are working only with ASCII characters, then this cop can be safely enabled.

Examples:

# bad
str.downcase == 'abc'
str.upcase.eql? 'ABC'
'abc' == str.downcase
'ABC'.eql? str.upcase
str.downcase == str.downcase

# good
str.casecmp('ABC').zero?
'abc'.casecmp(str).zero?

Constant Summary collapse

MSG = 
'Use `%<good>s` instead of `%<bad>s`.'
RESTRICT_ON_SEND = 
%i[== eql? !=].freeze
CASE_METHODS = 
%i[downcase upcase].freeze

Instance Method Summary collapse

Instance Method Details

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/casecmp.rb', line 58

def on_send(node)
  return unless downcase_eq(node) || eq_downcase(node)
  return unless (parts = take_method_apart(node))

  _receiver, method, arg, variable = parts
  good_method = build_good_method(method, arg, variable)

  message = format(MSG, good: good_method, bad: node.source)
  add_offense(node, message: message) do |corrector|
    autocorrect(corrector, node, good_method)
  end
end