class RuboCop::Cop::Style::CombinableLoops
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.
NOTE: Autocorrection is not applied when the block variable names differ in separate loops, as it is impossible to determine which variable name should be prioritized.
@safety
The cop is unsafe, because the first loop might modify state that the second loop depends on; these two aren't combinable.
@example
# 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
Constants
- MSG
Public Instance Methods
on_block(node)
click to toggle source
rubocop:disable Metrics/CyclomaticComplexity
# File lib/rubocop/cop/style/combinable_loops.rb, line 68 def on_block(node) return unless node.parent&.begin_type? return unless collection_looping_method?(node) return unless same_collection_looping_block?(node, node.left_sibling) return unless node.body && node.left_sibling.body add_offense(node) do |corrector| next unless node.arguments == node.left_sibling.arguments combine_with_left_sibling(corrector, node) end end
Also aliased as: on_numblock
on_for(node)
click to toggle source
# File lib/rubocop/cop/style/combinable_loops.rb, line 84 def on_for(node) return unless node.parent&.begin_type? return unless same_collection_looping_for?(node, node.left_sibling) add_offense(node) do |corrector| combine_with_left_sibling(corrector, node) end end
Private Instance Methods
collection_looping_method?(node)
click to toggle source
# File lib/rubocop/cop/style/combinable_loops.rb, line 95 def collection_looping_method?(node) method_name = node.method_name method_name.start_with?('each') || method_name.end_with?('_each') end
combine_with_left_sibling(corrector, node)
click to toggle source
# File lib/rubocop/cop/style/combinable_loops.rb, line 112 def combine_with_left_sibling(corrector, node) corrector.remove(node.left_sibling.body.source_range.end.join(node.left_sibling.loc.end)) corrector.remove(node.source_range.begin.join(node.body.source_range.begin)) correct_end_of_block(corrector, node) end
correct_end_of_block(corrector, node)
click to toggle source
# File lib/rubocop/cop/style/combinable_loops.rb, line 119 def correct_end_of_block(corrector, node) return unless node.left_sibling.respond_to?(:braces?) return if node.right_sibling&.block_type? || node.right_sibling&.numblock_type? end_of_block = node.left_sibling.braces? ? '}' : ' end' corrector.remove(node.loc.end) corrector.insert_before(node.source_range.end, end_of_block) end
same_collection_looping_block?(node, sibling)
click to toggle source
# File lib/rubocop/cop/style/combinable_loops.rb, line 100 def same_collection_looping_block?(node, sibling) return false if sibling.nil? || (!sibling.block_type? && !sibling.numblock_type?) sibling.method?(node.method_name) && sibling.receiver == node.receiver && sibling.send_node.arguments == node.send_node.arguments end
same_collection_looping_for?(node, sibling)
click to toggle source
# File lib/rubocop/cop/style/combinable_loops.rb, line 108 def same_collection_looping_for?(node, sibling) sibling&.for_type? && node.collection == sibling.collection end