Class: RuboCop::Cop::Style::RedundantSort

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

Overview

This cop is used to identify instances of sorting and then taking only the first or last element. The same behavior can be accomplished without a relatively expensive sort by using ‘Enumerable#min` instead of sorting and taking the first element and `Enumerable#max` instead of sorting and taking the last element. Similarly, `Enumerable#min_by` and `Enumerable#max_by` can replace `Enumerable#sort_by` calls after which only the first or last element is used.

Examples:

# bad
[2, 1, 3].sort.first
[2, 1, 3].sort[0]
[2, 1, 3].sort.at(0)
[2, 1, 3].sort.slice(0)

# good
[2, 1, 3].min

# bad
[2, 1, 3].sort.last
[2, 1, 3].sort[-1]
[2, 1, 3].sort.at(-1)
[2, 1, 3].sort.slice(-1)

# good
[2, 1, 3].max

# bad
arr.sort_by(&:foo).first
arr.sort_by(&:foo)[0]
arr.sort_by(&:foo).at(0)
arr.sort_by(&:foo).slice(0)

# good
arr.min_by(&:foo)

# bad
arr.sort_by(&:foo).last
arr.sort_by(&:foo)[-1]
arr.sort_by(&:foo).at(-1)
arr.sort_by(&:foo).slice(-1)

# good
arr.max_by(&:foo)

Constant Summary collapse

MSG = 
'Use `%<suggestion>s` instead of '\
'`%<sorter>s...%<accessor_source>s`.'
RESTRICT_ON_SEND = 
%i[sort sort_by].freeze

Constants included from Util

Util::LITERAL_REGEX

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#add_global_offense, #add_offense, autocorrect_incompatible_with, badge, callbacks_needed, #callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, joining_forces, lint?, match?, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #ready, #relevant_file?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from AutocorrectLogic

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

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

add_parentheses, args_begin, args_end, begins_its_line?, comment_line?, comment_lines?, double_quotes_required?, escape_string, first_part_of_call_chain, indent, interpret_string_escapes, line_range, needs_escaping?, on_node, parentheses?, same_line?, to_string_literal, to_supported_styles, trim_string_interporation_escape_character

Methods included from PathUtil

absolute?, hidden_dir?, hidden_file?, hidden_file_in_not_hidden_dir?, match_path?, maybe_hidden_file?, relative_path, smart_path

Constructor Details

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

Instance Method Details

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_sort.rb', line 77

def on_send(node)
  if (sort_node, sorter, accessor = redundant_sort?(node.parent))
    ancestor = node.parent
  elsif (sort_node, sorter, accessor = redundant_sort?(node.parent&.parent))
    ancestor = node.parent.parent
  else
    return
  end

  message = message(ancestor, sorter, accessor)

  add_offense(offense_range(sort_node, ancestor), message: message) do |corrector|
    autocorrect(corrector, ancestor, sort_node, sorter, accessor)
  end
end