class RubbyCop::Cop::Style::ZeroLengthPredicate

This cop checks for numeric comparisons that can be replaced by a predicate method, such as receiver.length == 0, receiver.length > 0, receiver.length != 0, receiver.length < 1 and receiver.size == 0 that can be replaced by receiver.empty? and !receiver.empty.

@example

@bad
[1, 2, 3].length == 0
0 == "foobar".length
array.length < 1
{a: 1, b: 2}.length != 0
string.length > 0
hash.size > 0

@good
[1, 2, 3].empty?
"foobar".empty?
array.empty?
!{a: 1, b: 2}.empty?
!string.empty?
!hash.empty?

Constants

NONZERO_MSG
ZERO_MSG

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubbycop/cop/style/zero_length_predicate.rb, line 63
def autocorrect(node)
  lambda do |corrector|
    corrector.replace(node.loc.expression, replacement(node))
  end
end
on_send(node) click to toggle source
# File lib/rubbycop/cop/style/zero_length_predicate.rb, line 33
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)

  # rubbycop:disable Style/GuardClause
  if nonzero_length_predicate
    add_offense(node, :expression,
                format(NONZERO_MSG, *nonzero_length_predicate))
  end
  # rubbycop:enable Style/GuardClause
end
replacement(node) click to toggle source
# File lib/rubbycop/cop/style/zero_length_predicate.rb, line 69
def replacement(node)
  receiver = zero_length_receiver(node)
  return "#{receiver.source}.empty?" if receiver

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