Class: RuboCop::Cop::Performance::Size

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

Overview

This cop is used to identify usages of count on an Array and Hash and change them to size.

TODO: Add advanced detection of variables that could have been assigned to an array or a hash.

Examples:

# bad
[1, 2, 3].count

# bad
{a: 1, b: 2, c: 3}.count

# good
[1, 2, 3].size

# good
{a: 1, b: 2, c: 3}.size

# good
[1, 2, 3].count { |e| e > 2 }

Constant Summary collapse

MSG =
'Use `size` instead of `count`.'

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?, #excluded_file?, inherited, #initialize, #join_force?, lint?, match?, #message, 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/size.rb', line 41

def autocorrect(node)
  ->(corrector) { corrector.replace(node.loc.selector, 'size') }
end

#on_send(node) ⇒ Object



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# File 'lib/rubocop/cop/performance/size.rb', line 29

def on_send(node)
  receiver, method, args = *node

  return if receiver.nil?
  return unless method == :count
  return unless array?(receiver) || hash?(receiver)
  return if node.parent && node.parent.block_type?
  return if args && args.block_pass_type?

  add_offense(node, node.loc.selector)
end