Class: RuboCop::Cop::Performance::StringReplacement

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/performance/string_replacement.rb

Overview

This cop identifies places where gsub can be replaced by tr or delete.

Examples:

@bad
'abc'.gsub('b', 'd')
'abc'.gsub('a', '')
'abc'.gsub(/a/, 'd')
'abc'.gsub!('a', 'd')

@good
'abc'.gsub(/.*/, 'a')
'abc'.gsub(/a+/, 'd')
'abc'.tr('b', 'd')
'a b c'.delete(' ')

Constant Summary collapse

MSG = 
'Use `%s` instead of `%s`.'
DETERMINISTIC_REGEX = 
/^[\w\s\-,."']+$/
REGEXP_CONSTRUCTOR_METHODS = 
[:new, :compile]
GSUB_METHODS = 
[:gsub, :gsub!]
DETERMINISTIC_TYPES = 
[:regexp, :str, :send]

Constants included from Util

Util::ASGN_NODES, Util::EQUALS_ASGN_NODES, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, cop_type, #correct, #debug?, #display_cop_names?, #display_style_guide?, inherited, #initialize, #join_force?, lint?, match?, non_rails, qualified_cop_name, rails?, #reference_url, #relevant_file?, #style_guide_url

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, directions, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, move_pos, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_comma, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

hidden?, issue_deprecation_warning, match_path?, relative_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#autocorrect(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/string_replacement.rb', line 50

def autocorrect(node)
  _string, method, first_param, second_param = *node
  first_source = first_source(first_param)
  second_source, = *second_param
  replacement_method = replacement_method(first_source, second_source)

  lambda do |corrector|
    replacement =
      if second_source.empty? && first_source.length == 1
        "#{replacement_method}#{'!' if bang_method?(method)}" \
        "(#{escape(first_source)})"
      else
        "#{replacement_method}#{'!' if bang_method?(method)}" \
        "(#{escape(first_source)}, #{escape(second_source)})"
      end

    corrector.replace(range(node), replacement)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/string_replacement.rb', line 28

def on_send(node)
  _string, method, first_param, second_param = *node
  return unless GSUB_METHODS.include?(method)
  return unless second_param && second_param.str_type?
  return unless DETERMINISTIC_TYPES.include?(first_param.type)

  first_source = first_source(first_param)
  second_source, = *second_param

  return if first_source.nil?

  if regex?(first_param)
    return unless first_source =~ DETERMINISTIC_REGEX
  end

  return if first_source.length != 1
  return unless second_source.length <= 1

  message = message(method, first_source, second_source)
  add_offense(node, range(node), message)
end