class RuboCop::Cop::Style::ZeroLengthPredicate

This cop checks for receiver.length == 0 predicates and the negated versions receiver.length > 0 and receiver.length != 0. These can be replaced with receiver.empty? and !receiver.empty? respectively.

@example

@bad
[1, 2, 3].length == 0
0 == "foobar".length
hash.size > 0

@good
[1, 2, 3].empty?
"foobar".empty?
!hash.empty?

Constants

NONZERO_MSG
ZERO_MSG

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubocop/cop/style/zero_length_predicate.rb, line 54
def autocorrect(node)
  lambda do |corrector|
    corrector.replace(node.loc.expression, replacement(node))
  end
end
on_send(node) click to toggle source
# File lib/rubocop/cop/style/zero_length_predicate.rb, line 26
def on_send(node)
  zero_length_predicate = zero_length_predicate(node)

  if zero_length_predicate
    add_offense(node, :expression,
                format(ZERO_MSG, *zero_length_predicate))
  end

  nonzero_length_predicate = nonzero_length_predicate(node)

  if nonzero_length_predicate
    add_offense(node, :expression,
                format(NONZERO_MSG, *nonzero_length_predicate))
  end
end
replacement(node) click to toggle source
# File lib/rubocop/cop/style/zero_length_predicate.rb, line 60
def replacement(node)
  receiver = zero_length_receiver(node)
  return "#{receiver.source}.empty?" if receiver

  "!#{other_receiver(node).source}.empty?"
end