Class: RuboCop::Cop::Performance::CompareWithBlock

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

Overview

This cop identifies places where ‘sort { |a, b| a.foo <=> b.foo }` can be replaced by `sort_by(&:foo)`. This cop also checks `max` and `min` methods.

Examples:

# bad
array.sort { |a, b| a.foo <=> b.foo }
array.max { |a, b| a.foo <=> b.foo }
array.min { |a, b| a.foo <=> b.foo }
array.sort { |a, b| a[:foo] <=> b[:foo] }

# good
array.sort_by(&:foo)
array.sort_by { |v| v.foo }
array.sort_by do |var|
  var.foo
end
array.max_by(&:foo)
array.min_by(&:foo)
array.sort_by { |a| a[:foo] }

Constant Summary collapse

MSG = 
'Use `%<compare_method>s_by%<instead>s` instead of ' \
'`%<compare_method>s { |%<var_a>s, %<var_b>s| %<str_a>s ' \
'<=> %<str_b>s }`.'.freeze

Constants included from Util

Util::ASGN_NODES, Util::BYTE_ORDER_MARK, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, 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, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

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?, comment_line?, double_quotes_required?, effective_column, ends_its_line?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, operator?, parentheses?, parenthesized_call?, precede?, range_between, range_by_whole_lines, range_with_surrounding_comma, range_with_surrounding_space, same_line?, source_range, strip_quotes, stripped_source_upto, symbol_without_quote?, to_string_literal, to_supported_styles, to_symbol_literal, within_node?

Methods included from PathUtil

absolute?, find_file_upwards, match_path?, pwd, relative_path, reset_pwd, smart_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/compare_with_block.rb', line 60

def autocorrect(node)
  lambda do |corrector|
    send, var_a, var_b, body = compare?(node)
    method, arg, = replaceable_body?(body, var_a, var_b)
    replacement =
      if method == :[]
        "#{send.method_name}_by { |a| a[#{arg.first.source}] }"
      else
        "#{send.method_name}_by(&:#{method})"
      end
    corrector.replace(compare_range(send, node),
                      replacement)
  end
end

#on_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/performance/compare_with_block.rb', line 45

def on_block(node)
  compare?(node) do |send, var_a, var_b, body|
    replaceable_body?(body, var_a, var_b) do |method, args_a, args_b|
      return unless slow_compare?(method, args_a, args_b)
      range = compare_range(send, node)

      add_offense(
        node,
        location: range,
        message: message(send, method, var_a, var_b, args_a)
      )
    end
  end
end