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Rails blank.rb implementation (for use over empty and nil)
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# encoding: utf-8 | |
class Object | |
# An object is blank if it's false, empty, or a whitespace string. | |
# For example, '', ' ', +nil+, [], and {} are all 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 <tt>present?</tt> otherwise returns +nil+. | |
# <tt>object.presence</tt> is equivalent to <tt>object.present? ? object : nil</tt>. | |
# | |
# 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 | |
# +nil+ is blank: | |
# | |
# nil.blank? # => true | |
def blank? | |
true | |
end | |
end | |
class FalseClass | |
# +false+ is blank: | |
# | |
# false.blank? # => true | |
def blank? | |
true | |
end | |
end | |
class TrueClass | |
# +true+ is not blank: | |
# | |
# true.blank? # => false | |
def blank? | |
false | |
end | |
end | |
class Array | |
# An array is blank if it's empty: | |
# | |
# [].blank? # => true | |
# [1,2,3].blank? # => false | |
alias_method :blank?, :empty? | |
end | |
class Hash | |
# A hash is blank if it's empty: | |
# | |
# {}.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: | |
# | |
# ''.blank? # => true | |
# ' '.blank? # => true | |
# ' '.blank? # => true | |
# ' something here '.blank? # => false | |
def blank? | |
self !~ /[^[:space:]]/ | |
end | |
end | |
class Numeric #:nodoc: | |
# No number is blank: | |
# | |
# 1.blank? # => false | |
# 0.blank? # => false | |
def blank? | |
false | |
end | |
end |
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