class RubbyCop::Cop::Style::InverseMethods

This cop check for usages of not (`not` or `!`) called on a method when an inverse of that method can be used instead. Methods that can be inverted by a not (`not` or `!`) should be defined in `InverseMethods` Methods that are inverted by inverting the return of the block that is passed to the method should be defined in `InverseBlocks`

@example

# bad
!foo.none?
!foo.any? { |f| f.even? }
!foo.blank?
!(foo == bar)
foo.select { |f| !f.even? }
foo.reject { |f| f != 7 }

# good
foo.none?
foo.blank?
foo.any? { |f| f.even? }
foo != bar
foo == bar

Constants

EQUALITY_METHODS
MSG

Public Instance Methods

autocorrect(node) click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 71
def autocorrect(node)
  method_call, method = inverse_candidate?(node)

  if method_call && method
    lambda do |corrector|
      corrector.remove(not_to_receiver(node, method_call))
      corrector.replace(method_call.loc.selector,
                        inverse_methods[method].to_s)

      if EQUALITY_METHODS.include?(method)
        corrector.remove(end_parentheses(node, method_call))
      end
    end
  else
    correct_inverse_block(node)
  end
end
correct_inverse_block(node) click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 89
def correct_inverse_block(node)
  method_call, method, block = inverse_block?(node)
  selector = block.loc.selector.source

  lambda do |corrector|
    corrector.replace(method_call.loc.selector,
                      inverse_blocks[method].to_s)

    if ['!=', '!~'].include?(selector)
      selector[0] = '='
      corrector.replace(block.loc.selector, selector)
    else
      corrector.remove(block.loc.selector)
    end
  end
end
end_parentheses(node, method_call) click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 122
def end_parentheses(node, method_call)
  Parser::Source::Range.new(node.loc.expression.source_buffer,
                            method_call.loc.expression.end_pos,
                            node.loc.expression.end_pos)
end
inverse_blocks() click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 111
def inverse_blocks
  @inverse_blocks ||= cop_config['InverseBlocks']
                      .merge(cop_config['InverseBlocks'].invert)
end
inverse_methods() click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 106
def inverse_methods
  @inverse_methods ||= cop_config['InverseMethods']
                       .merge(cop_config['InverseMethods'].invert)
end
not_to_receiver(node, method_call) click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 116
def not_to_receiver(node, method_call)
  Parser::Source::Range.new(node.loc.expression.source_buffer,
                            node.loc.selector.begin_pos,
                            method_call.loc.expression.begin_pos)
end
on_block(node) click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 60
def on_block(node)
  inverse_block?(node) do |_method_call, method, _block|
    return unless inverse_blocks.key?(method)

    add_offense(node,
                :expression,
                format(MSG, method: method,
                            inverse: inverse_blocks[method]))
  end
end
on_send(node) click to toggle source
# File lib/rubbycop/cop/style/inverse_methods.rb, line 49
def on_send(node)
  inverse_candidate?(node) do |_method_call, method|
    return unless inverse_methods.key?(method)

    add_offense(node,
                :expression,
                format(MSG, method: method,
                            inverse: inverse_methods[method]))
  end
end