Class: RuboCop::Cop::Style::MultipleComparison

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

Overview

Checks against comparing a variable with multiple items, where ‘Array#include?`, `Set#include?` or a `case` could be used instead to avoid code repetition. It accepts comparisons of multiple method calls to avoid unnecessary method calls by default. It can be configured by `AllowMethodComparison` option.

Examples:

# bad
a = 'a'
foo if a == 'a' || a == 'b' || a == 'c'

# good
a = 'a'
foo if ['a', 'b', 'c'].include?(a)

VALUES = Set['a', 'b', 'c'].freeze
# elsewhere...
foo if VALUES.include?(a)

case foo
when 'a', 'b', 'c' then foo
# ...
end

# accepted (but consider `case` as above)
foo if a == b.lightweight || a == b.heavyweight

AllowMethodComparison: true (default)

# good
foo if a == b.lightweight || a == b.heavyweight

AllowMethodComparison: false

# bad
foo if a == b.lightweight || a == b.heavyweight

# good
foo if [b.lightweight, b.heavyweight].include?(a)

ComparisonsThreshold: 2 (default)

# bad
foo if a == 'a' || a == 'b'

ComparisonsThreshold: 3

# good
foo if a == 'a' || a == 'b'

Constant Summary collapse

MSG = 
'Avoid comparing a variable with multiple items ' \
'in a conditional, use `Array#include?` instead.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#on_new_investigation ⇒ Object 



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# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 58

def on_new_investigation
  @last_comparison = nil
end

#on_or(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/multiple_comparison.rb', line 62

def on_or(node)
  reset_comparison if switch_comparison?(node)

  root_of_or_node = root_of_or_node(node)

  return unless node == root_of_or_node
  return unless nested_variable_comparison?(root_of_or_node)
  return if @allowed_method_comparison
  return if @compared_elements.size < comparisons_threshold

  add_offense(node) do |corrector|
    elements = @compared_elements.join(', ')
    prefer_method = "[#{elements}].include?(#{variables_in_node(node).first})"

    corrector.replace(node, prefer_method)
  end

  @last_comparison = node
end