class RuboCop::Cop::Performance::Detect
This cop is used to identify usages of `select.first`, `select.last`, `find_all.first`, and `find_all.last` and change them to use `detect` instead.
@example
# bad [].select { |item| true }.first [].select { |item| true }.last [].find_all { |item| true }.first [].find_all { |item| true }.last # good [].detect { |item| true } [].reverse.detect { |item| true }
`ActiveRecord` compatibility: `ActiveRecord` does not implement a `detect` method and `find` has its own meaning. Correcting ActiveRecord methods with this cop should be considered unsafe.
Constants
- MSG
- REVERSE_MSG
Public Instance Methods
autocorrect(node)
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# File lib/rubocop/cop/performance/detect.rb, line 51 def autocorrect(node) receiver, first_method = *node replacement = if first_method == :last "reverse.#{preferred_method}" else preferred_method end first_range = receiver.source_range.end.join(node.loc.selector) receiver, _args, _body = *receiver if receiver.block_type? lambda do |corrector| corrector.remove(first_range) corrector.replace(receiver.loc.selector, replacement) end end
on_send(node)
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# File lib/rubocop/cop/performance/detect.rb, line 37 def on_send(node) return if rails_safe_mode? detect_candidate?(node) do |receiver, second_method, args| return unless args.empty? return unless receiver receiver, _args, body = *receiver if receiver.block_type? return if accept_first_call?(receiver, body) register_offense(node, receiver, second_method) end end
Private Instance Methods
accept_first_call?(receiver, body)
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# File lib/rubocop/cop/performance/detect.rb, line 72 def accept_first_call?(receiver, body) caller, _first_method, args = *receiver # check that we have usual block or block pass return true if body.nil? && (args.nil? || !args.block_pass_type?) lazy?(caller) end
lazy?(node)
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# File lib/rubocop/cop/performance/detect.rb, line 97 def lazy?(node) return false unless node receiver, method, _args = *node method == :lazy && !receiver.nil? end
preferred_method()
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# File lib/rubocop/cop/performance/detect.rb, line 92 def preferred_method config.for_cop('Style/CollectionMethods') \ ['PreferredMethods']['detect'] || 'detect' end
register_offense(node, receiver, second_method)
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# File lib/rubocop/cop/performance/detect.rb, line 81 def register_offense(node, receiver, second_method) _caller, first_method, _args = *receiver range = receiver.loc.selector.join(node.loc.selector) message = second_method == :last ? REVERSE_MSG : MSG formatted_message = format(message, preferred_method, first_method, second_method) add_offense(node, location: range, message: formatted_message) end