activesupport/lib/active_support/core_ext/blank.rb


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class Object
  # An object is blank if it's nil, empty, or a whitespace string.
  # For example, "", "   ", nil, [], and {} are blank.
  #
  # This simplifies
  #   if !address.nil? && !address.empty?
  # to
  #   if !address.blank?
  def blank?
    if respond_to?(:empty?) && respond_to?(:strip)
      empty? or strip.empty?
    elsif respond_to?(:empty?)
      empty?
    else
      !self
    end
  end
end

class NilClass #:nodoc:
  def blank?
    true
  end
end

class FalseClass #:nodoc:
  def blank?
    true
  end
end

class TrueClass #:nodoc:
  def blank?
    false
  end
end

class Array #:nodoc:
  alias_method :blank?, :empty?
end

class Hash #:nodoc:
  alias_method :blank?, :empty?
end

class String #:nodoc:
  def blank?
    empty? || strip.empty?
  end
end

class Numeric #:nodoc:
  def blank?
    false
  end
end