class RuboCop::Cop::Performance::CompareWithBlock
This cop identifies places where `sort { |a, b| a.foo <=> b.foo }` can be replaced by `sort_by(&:foo)`. This cop also checks `max` and `min` methods.
@example
# bad array.sort { |a, b| a.foo <=> b.foo } array.max { |a, b| a.foo <=> b.foo } array.min { |a, b| a.foo <=> b.foo } array.sort { |a, b| a[:foo] <=> b[:foo] } # good array.sort_by(&:foo) array.sort_by { |v| v.foo } array.sort_by do |var| var.foo end array.max_by(&:foo) array.min_by(&:foo) array.sort_by { |a| a[:foo] }
Constants
- MSG
Public Instance Methods
autocorrect(node)
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# File lib/rubocop/cop/performance/compare_with_block.rb, line 63 def autocorrect(node) lambda do |corrector| send, var_a, var_b, body = compare?(node) method, arg, = replaceable_body?(body, var_a, var_b) replacement = if method == :[] "#{send.method_name}_by { |a| a[#{arg.first.source}] }" else "#{send.method_name}_by(&:#{method})" end corrector.replace(compare_range(send, node), replacement) end end
on_block(node)
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# File lib/rubocop/cop/performance/compare_with_block.rb, line 47 def on_block(node) compare?(node) do |send, var_a, var_b, body| replaceable_body?(body, var_a, var_b) do |method, args_a, args_b| return unless slow_compare?(method, args_a, args_b) range = compare_range(send, node) add_offense( node, location: range, message: message(send, method, var_a, var_b, args_a) ) end end end
Private Instance Methods
compare_range(send, node)
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rubocop:enable Metrics/MethodLength
# File lib/rubocop/cop/performance/compare_with_block.rb, line 116 def compare_range(send, node) range_between(send.loc.selector.begin_pos, node.loc.end.end_pos) end
message(send, method, var_a, var_b, args)
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rubocop:disable Metrics/MethodLength
# File lib/rubocop/cop/performance/compare_with_block.rb, line 95 def message(send, method, var_a, var_b, args) compare_method = send.method_name if method == :[] key = args.first instead = " { |a| a[#{key.source}] }" str_a = "#{var_a}[#{key.source}]" str_b = "#{var_b}[#{key.source}]" else instead = "(&:#{method})" str_a = "#{var_a}.#{method}" str_b = "#{var_b}.#{method}" end format(MSG, compare_method: compare_method, instead: instead, var_a: var_a, var_b: var_b, str_a: str_a, str_b: str_b) end
slow_compare?(method, args_a, args_b)
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# File lib/rubocop/cop/performance/compare_with_block.rb, line 80 def slow_compare?(method, args_a, args_b) return false unless args_a == args_b if method == :[] return false unless args_a.size == 1 key = args_a.first return false unless %i[sym str int].include?(key.type) else return false unless args_a.empty? end true end