class RuboCop::Cop::Rails::Blank

This cop checks for code that can be written with simpler conditionals using `Object#blank?` defined by Active Support.

This cop is marked as unsafe auto-correction, because `' '.empty?` returns false, but `' '.blank?` returns true. Therefore, auto-correction is not compatible if the receiver is a non-empty blank string, tab, or newline meta characters.

Interaction with `Style/UnlessElse`: The configuration of `NotPresent` will not produce an offense in the context of `unless else` if `Style/UnlessElse` is inabled. This is to prevent interference between the auto-correction of the two cops.

@example NilOrEmpty: true (default)

# Converts usages of `nil? || empty?` to `blank?`

# bad
foo.nil? || foo.empty?
foo == nil || foo.empty?

# good
foo.blank?

@example NotPresent: true (default)

# Converts usages of `!present?` to `blank?`

# bad
!foo.present?

# good
foo.blank?

@example UnlessPresent: true (default)

# Converts usages of `unless present?` to `if blank?`

# bad
something unless foo.present?

# good
something if foo.blank?

# bad
unless foo.present?
  something
end

# good
if foo.blank?
  something
end

# good
def blank?
  !present?
end

Constants

MSG_NIL_OR_EMPTY
MSG_NOT_PRESENT
MSG_UNLESS_PRESENT
RESTRICT_ON_SEND

Public Instance Methods

on_if(node) click to toggle source
# File lib/rubocop/cop/rails/blank.rb, line 123
def on_if(node)
  return unless cop_config['UnlessPresent']
  return unless node.unless?
  return if node.else? && config.for_cop('Style/UnlessElse')['Enabled']

  unless_present?(node) do |method_call, receiver|
    range = unless_condition(node, method_call)

    message = format(MSG_UNLESS_PRESENT, prefer: replacement(receiver), current: range.source)
    add_offense(range, message: message) do |corrector|
      autocorrect(corrector, node)
    end
  end
end
on_or(node) click to toggle source
# File lib/rubocop/cop/rails/blank.rb, line 110
def on_or(node)
  return unless cop_config['NilOrEmpty']

  nil_or_empty?(node) do |var1, var2|
    return unless var1 == var2

    message = format(MSG_NIL_OR_EMPTY, prefer: replacement(var1), current: node.source)
    add_offense(node, message: message) do |corrector|
      autocorrect(corrector, node)
    end
  end
end
on_send(node) click to toggle source
# File lib/rubocop/cop/rails/blank.rb, line 96
def on_send(node)
  return unless cop_config['NotPresent']

  not_present?(node) do |receiver|
    # accepts !present? if its in the body of a `blank?` method
    next if defining_blank?(node.parent)

    message = format(MSG_NOT_PRESENT, prefer: replacement(receiver), current: node.source)
    add_offense(node, message: message) do |corrector|
      autocorrect(corrector, node)
    end
  end
end

Private Instance Methods

autocorrect(corrector, node) click to toggle source
# File lib/rubocop/cop/rails/blank.rb, line 140
def autocorrect(corrector, node)
  method_call, variable1 = unless_present?(node)

  if method_call
    corrector.replace(node.loc.keyword, 'if')
    range = method_call.loc.expression
  else
    variable1, _variable2 = nil_or_empty?(node) || not_present?(node)
    range = node.loc.expression
  end

  corrector.replace(range, replacement(variable1))
end
replacement(node) click to toggle source
# File lib/rubocop/cop/rails/blank.rb, line 162
def replacement(node)
  node.respond_to?(:source) ? "#{node.source}.blank?" : 'blank?'
end
unless_condition(node, method_call) click to toggle source
# File lib/rubocop/cop/rails/blank.rb, line 154
def unless_condition(node, method_call)
  if node.modifier_form?
    node.loc.keyword.join(node.loc.expression.end)
  else
    node.loc.expression.begin.join(method_call.loc.expression)
  end
end