# frozen_string_literal: true module RuboCop module Cop module Layout # This cop checks for spaces between -> and opening parameter # brace 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 < Cop include ConfigurableEnforcedStyle ARROW = '->'.freeze MSG_REQUIRE_SPACE = 'Use a space between `->` and opening brace ' \ 'in lambda literals'.freeze MSG_REQUIRE_NO_SPACE = 'Do not use spaces between `->` and opening ' \ 'brace in lambda literals'.freeze def on_send(node) return unless arrow_lambda_with_args?(node) if style == :require_space && !space_after_arrow?(node) add_offense(node, node.parent.loc.expression, MSG_REQUIRE_SPACE) elsif style == :require_no_space && space_after_arrow?(node) add_offense(node, node.parent.loc.expression, MSG_REQUIRE_NO_SPACE) end end def autocorrect(lambda_node) children = lambda_node.parent.children lambda do |corrector| if style == :require_space corrector.insert_before(children[1].source_range, ' ') else space_range = range_between(children[0].source_range.end_pos, children[1].source_range.begin_pos) corrector.remove(space_range) end end end private def arrow_lambda_with_args?(node) lambda_node?(node) && arrow_form?(node) && args?(node) end def lambda_node?(node) receiver, call = *node receiver.nil? && call == :lambda end def arrow_form?(lambda_node) lambda_node.loc.selector.source == ARROW end def args?(lambda_node) _call, args, _body = *lambda_node.parent !args.children.empty? end def space_after_arrow?(lambda_node) arrow = lambda_node.parent.children[0] parentheses = lambda_node.parent.children[1] parentheses.source_range.begin_pos - arrow.source_range.end_pos > 0 end end end end end