Active Model ImmutableString Type

Attribute type to represent immutable strings. It casts incoming values to frozen strings.

class Person
  include ActiveModel::Attributes

  attribute :name, :immutable_string
end

person = Person.new
person.name = 1

person.name # => "1"
person.name.frozen? # => true

Values are coerced to strings using their to_s method. Boolean values are treated differently, however: true will be cast to "t" and false will be cast to "f". These strings can be customized when declaring an attribute:

class Person
  include ActiveModel::Attributes

  attribute :active, :immutable_string, true: "aye", false: "nay"
end

person = Person.new
person.active = true

person.active # => "aye"

Methods

Class Public methods

new(**args)

📝 Source code 
# File activemodel/lib/active_model/type/immutable_string.rb, line 38
      def initialize(**args)
        @true  = -(args.delete(:true)&.to_s  || "t")
        @false = -(args.delete(:false)&.to_s || "f")
        super
      end
🔎 See on GitHub

Instance Public methods

serialize(value)

📝 Source code 
# File activemodel/lib/active_model/type/immutable_string.rb, line 48
      def serialize(value)
        case value
        when ::Numeric, ::Symbol, ActiveSupport::Duration then value.to_s
        when true then @true
        when false then @false
        else super
        end
      end
🔎 See on GitHub

type()

📝 Source code 
# File activemodel/lib/active_model/type/immutable_string.rb, line 44
      def type
        :string
      end
🔎 See on GitHub