Getting Started

Using Dry::Types in Your Application

  1. Make Dry::Types available to the application by creating a namespace that includes Dry::Types:

    module Types
     include Dry.Types()
    end
    
  2. Reload the environment, & type Types::Coercible::String in the ruby console to confirm it worked:

    Types::Coercible::String
    # => #<Dry::Types::Constructor type=#<Dry::Types::Definition primitive=String options={}>>
    

Creating Your First Type

  1. Define a struct's types by passing the name & type to the attribute method:

    class User < Dry::Struct
      attribute :name, Types::String
    end
    
  2. Define Custom Types in the Types module, then pass the name & type to attribute:

    module Types
      include Dry.Types()
    
      Email = String.constrained(format: /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z]+)*\.[a-z]+\z/i)
      Age = Integer.constrained(gt: 18)
    end
    class User < Dry::Struct
      attribute :name, Types::String
      attribute :email, Types::Email
      attribute :age, Types::Age
    end
    
  3. Use a Dry::Struct as a type:

    class Message < Dry::Struct
      attribute :body, Types::String
      attribute :to, User
    end