Class: RuboCop::Cop::Style::CombinableLoops

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/style/combinable_loops.rb

Overview

This cop checks for places where multiple consecutive loops over the same data can be combined into a single loop. It is very likely that combining them will make the code more efficient and more concise.

It is marked as unsafe, because the first loop might modify a state that the second loop depends on; these two aren't combinable.

Examples:

# bad
def method
  items.each do |item|
    do_something(item)
  end

  items.each do |item|
    do_something_else(item)
  end
end

# good
def method
  items.each do |item|
    do_something(item)
    do_something_else(item)
  end
end

# bad
def method
  for item in items do
    do_something(item)
  end

  for item in items do
    do_something_else(item)
  end
end

# good
def method
  for item in items do
    do_something(item)
    do_something_else(item)
  end
end

# good
def method
  each_slice(2) { |slice| do_something(slice) }
  each_slice(3) { |slice| do_something(slice) }
end

Constant Summary collapse

MSG =
'Combine this loop with the previous loop.'

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

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?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, 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?, #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_block(node) ⇒ Object


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# File 'lib/rubocop/cop/style/combinable_loops.rb', line 61

def on_block(node)
  return unless node.parent&.begin_type?
  return unless collection_looping_method?(node)

  add_offense(node) if same_collection_looping?(node, node.left_sibling)
end

#on_for(node) ⇒ Object


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# File 'lib/rubocop/cop/style/combinable_loops.rb', line 68

def on_for(node)
  return unless node.parent&.begin_type?

  sibling = node.left_sibling
  add_offense(node) if sibling&.for_type? && node.collection == sibling.collection
end