Class: RuboCop::Cop::Style::EachWithObject

Inherits:
Cop
  • Object
show all
Includes:
RangeHelp
Defined in:
lib/rubocop/cop/style/each_with_object.rb

Overview

This cop looks for inject / reduce calls where the passed in object is returned at the end and so could be replaced by each_with_object without the need to return the object at the end.

However, we can’t replace with each_with_object if the accumulator parameter is assigned to within the block.

Examples:

# bad
[1, 2].inject({}) { |a, e| a[e] = e; a }

# good
[1, 2].each_with_object({}) { |e, a| a[e] = e }

Constant Summary collapse

MSG = 
'Use `each_with_object` instead of `%<method>s`.'.freeze
METHODS = 
%i[inject reduce].freeze

Constants included from Util

Util::ASGN_NODES, 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?, #message, #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?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, operator?, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens

Methods included from PathUtil

absolute?, 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

rubocop:disable Metrics/AbcSize



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# File 'lib/rubocop/cop/style/each_with_object.rb', line 45

def autocorrect(node)
  lambda do |corrector|
    corrector.replace(node.send_node.loc.selector, 'each_with_object')

    first_arg, second_arg = *node.arguments

    corrector.replace(first_arg.loc.expression, second_arg.source)
    corrector.replace(second_arg.loc.expression, first_arg.source)

    return_value = return_value(node.body)

    if return_value_occupies_whole_line?(return_value)
      corrector.remove(whole_line_expression(return_value))
    else
      corrector.remove(return_value.loc.expression)
    end
  end
end

#on_block(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/each_with_object.rb', line 29

def on_block(node)
  each_with_object_candidate?(node) do |method, args, body|
    _, method_name, method_arg = *method
    return if simple_method_arg?(method_arg)

    return_value = return_value(body)
    return unless return_value
    return unless first_argument_returned?(args, return_value)
    return if accumulator_param_assigned_to?(body, args)

    add_offense(node, location: method.loc.selector,
                      message: format(MSG, method: method_name))
  end
end