lib/rubocop/cop/layout/space_in_lambda_literal.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Layout
# Checks for spaces between `->` and opening parameter
# parenthesis (`(`) in lambda literals.
#
# @example EnforcedStyle: require_no_space (default)
# # bad
# a = -> (x, y) { x + y }
#
# # good
# a = ->(x, y) { x + y }
#
# @example EnforcedStyle: require_space
# # bad
# a = ->(x, y) { x + y }
#
# # good
# a = -> (x, y) { x + y }
class SpaceInLambdaLiteral < Base
include ConfigurableEnforcedStyle
include RangeHelp
extend AutoCorrector
MSG_REQUIRE_SPACE = 'Use a space between `->` and `(` in lambda literals.'
MSG_REQUIRE_NO_SPACE = 'Do not use spaces between `->` and `(` in lambda literals.'
def on_send(node)
return unless arrow_lambda_with_args?(node)
if style == :require_space && !space_after_arrow?(node)
lambda_node = range_of_offense(node)
add_offense(lambda_node, message: MSG_REQUIRE_SPACE) do |corrector|
corrector.insert_before(lambda_arguments(node), ' ')
end
elsif style == :require_no_space && space_after_arrow?(node)
space = space_after_arrow(node)
add_offense(space, message: MSG_REQUIRE_NO_SPACE) do |corrector|
corrector.remove(space)
end
end
end
private
def arrow_lambda_with_args?(node)
node.lambda_literal? && node.parent.arguments?
end
def space_after_arrow?(lambda_node)
!space_after_arrow(lambda_node).empty?
end
def space_after_arrow(lambda_node)
arrow = lambda_node.parent.children[0].source_range
parentheses = lambda_node.parent.children[1].source_range
arrow.end.join(parentheses.begin)
end
def range_of_offense(node)
range_between(
node.parent.source_range.begin_pos,
node.parent.arguments.source_range.end_pos
)
end
def lambda_arguments(node)
node.parent.children[1]
end
end
end
end
end