Typelizer

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ActiveModel::Serializer ​

This guide covers using Typelizer with ActiveModel::Serializer (AMS).

Setup ​

ruby
class ApplicationSerializer < ActiveModel::Serializer
  include Typelizer::DSL
end

Attributes and Associations ​

Define attributes and associations as usual:

ruby
class PostSerializer < ApplicationSerializer
  attributes :id, :title, :body

  has_one :author, serializer: AuthorSerializer
  has_many :comments, serializer: CommentSerializer
  belongs_to :created_by, serializer: UserSerializer
end

Typelizer infers types from the model. Use typelize_from when the model name can't be inferred:

ruby
class AuthorSerializer < ApplicationSerializer
  typelize_from User
  attributes :id, :name
end

Conditional Attributes ​

Attributes with if: or unless: conditions are automatically marked as optional in the generated TypeScript:

ruby
class UserSerializer < ApplicationSerializer
  attributes :id, :name
  attribute :email, if: :admin?
end

Generates:

typescript
export type User = {
  id: number;
  name: string;
  email?: string;
}

Key Transformation ​

AMS adapter key transforms are respected:

ruby
class PostSerializer < ApplicationSerializer
  attributes :id, :title, :created_at
end

# config/initializers/ams.rb
ActiveModelSerializers.config.key_transform = :camel_lower

Custom Methods ​

Override attributes with methods and annotate with typelize:

ruby
class PostSerializer < ApplicationSerializer
  attributes :id, :title

  typelize :string
  attribute :name, deprecated: "Use 'title' instead."
  def name
    title
  end
end

See Manual Typing for full details on the typelize method.