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class Object
# An object is blank if it's false, empty, or a whitespace string.
# For example, "", " ", +nil+, [], and {} are blank.
#
# This simplifies:
#
# if !address.nil? && !address.empty?
#
# ...to:
#
# if !address.blank?
def blank?
respond_to?(:empty?) ? empty? : !self
end
# An object is present if it's not <tt>blank?</tt>.
def present?
!blank?
end
# Returns object if it's #present? otherwise returns nil.
# object.presence is equivalent to object.present? ? object : nil.
#
# This is handy for any representation of objects where blank is the same
# as not present at all. For example, this simplifies a common check for
# HTTP POST/query parameters:
#
# state = params[:state] if params[:state].present?
# country = params[:country] if params[:country].present?
# region = state || country || 'US'
#
# ...becomes:
#
# region = params[:state].presence || params[:country].presence || 'US'
def presence
self if present?
end
end
class NilClass
# Instances of NilClass are always blank
#
# === Example
#
# nil.blank? => true
def blank?
true
end
end
class FalseClass
# Instances of FalseClass are always blank
#
# === Example
#
# false.blank? => true
def blank?
true
end
end
class TrueClass
# Instances of TrueClass are never blank
#
# === Example
#
# true.blank? => false
def blank?
false
end
end
class Array
# An array is blank if it's empty
#
# === Examples
#
# [].blank? => true
# [1,2,3].blank? => false
alias_method :blank?, :empty?
end
class Hash
# A hash is blank if it's empty
#
# === Examples
#
# {}.blank? => true
# {:key => 'value'}.blank? => false
alias_method :blank?, :empty?
end
class String
# A string is blank if it's empty or contains whitespaces only
#
# === Examples
#
# "".blank? => true
# " ".blank? => true
# " something here ".blank? => false
def blank?
self !~ /\S/
end
end
class Numeric #:nodoc:
def blank?
false
end
end
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