gitlab-org--gitlab-foss/rubocop/cop/gitlab/keys_first_and_values_first.rb

57 lines
2 KiB
Ruby

# frozen_string_literal: true
module RuboCop
module Cop
module Gitlab
class KeysFirstAndValuesFirst < RuboCop::Cop::Cop
FIRST_PATTERN = /\Afirst\z/.freeze
def message(used_method)
<<~MSG
Don't use `.keys.first` and `.values.first`.
Instead use `.each_key.first` and `.each_value.first` (or `.first.first` and `first.second`)
This will reduce memory usage and execution time.
MSG
end
def on_send(node)
if find_on_keys_or_values?(node)
add_offense(node, location: :selector, message: message(node.method_name))
end
end
def autocorrect(node)
lambda do |corrector|
replace_with = if node.descendants.first.method_name == :values
'.each_value'
elsif node.descendants.first.method_name == :keys
'.each_key'
else
throw("Expect '.values.first' or '.keys.first', but get #{node.descendants.first.method_name}.first") # rubocop:disable Cop/BanCatchThrow
end
upto_including_keys_or_values = node.descendants.first.source_range
before_keys_or_values = node.descendants[1].source_range
range_to_replace = node.source_range
.with(begin_pos: before_keys_or_values.end_pos,
end_pos: upto_including_keys_or_values.end_pos)
corrector.replace(range_to_replace, replace_with)
end
end
def find_on_keys_or_values?(node)
chained_on_node = node.descendants.first
node.method_name.to_s =~ FIRST_PATTERN &&
chained_on_node.is_a?(RuboCop::AST::SendNode) &&
[:keys, :values].include?(chained_on_node.method_name) &&
node.descendants[1]
end
def method_name_for_node(node)
children[1].to_s
end
end
end
end
end