JustEnum

This gem has been created to mimic Typescript like enums and adding additional features to the POROs.

Installation

Add this line to your application's Gemfile:

gem 'just_enum'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install just_enum

Usage

Defining enums

After installing gem extend the class you want to make the enum for storing properties with JustEnum::Base.

For example:

class ButtonType < JustEnum::Base
  enum %i[primary secondary]
end

class Color < JustEnum::Base
  enum %i[success danger]
end

class Labels < JustEnum::Base
  enum({save: "Zapisz", cancel: "Anuluj"})
end

So that you can have enum classes as Ruby singletons. You can use:

ButtonType.primary #=> 0
ButtonType.secondary #=> 1
Color.success #=> 0
Color.danger #=> 1
Labels.save #=> "Zapisz"
Labels.cancel #=> "Anuluj"

You can list all possible options in the enum by using .options static method

ButtonType.options #=> [:primary, :secondary]
Color.options #=> {:success=>"success", :danger=>"danger"}
Labels.options #=> {:save=>"Zapisz", :cancel=>"Anuluj"}

How enums are defined in JustEnum

Indexed enum

class ButtonType < JustEnum::Base
  enum %i[primary secondary]
end

enum %i[primary secondary]

# is the same as:

{ primary: 0, secondary: 1 }

Enum with custom values

You can define custom values for enums

class Labels < JustEnum::Enum
  enum({ save: "Zapisz", cancel: "Anuluj" })
end

enum({ save: "Zapisz", cancel: "Anuluj" })

# is the same as:

{ save: "Zapisz", cancel: "Anuluj" }

Mirrored enum keys

You can mirror your keys as the values in enum.

class Color < JustEnum::Base
  enum %i[success danger], mirror: true
end

enum %i[success danger], mirror: true

# is the same as:

{ success: "success", danger: "danger" }

Use defined enums as values in your PORO classes.

Than You can use the enum to define values for fields in your PORO classes. Do it by extending your class with JustEnum::Enum

class ButtonPrimary
  extend JustEnum::Enum
  enumerate :type, ButtonType, ButtonType.primary
  enumerate :color, Color, Color.success
  enumerate :label, Labels, Labels.save
end

You can also omit the extend directive and use it in traditional way in constructor or attr_writer.

class ButtonPrimary
  def initialize
    @type = ButtonType.primary
    @color = Color.success
    @label = Labels.save
  end
end

Extend your class with `JustEnum::Enum`

When extending your PORO with JustEnum::Enum:

a) you can access the enumarate method which defines instance fields with values provided by enums

class ButtonPrimary
  extend JustEnum::Enum
  enumerate :type, ButtonType, ButtonType.primary
  enumerate :color, Color, Color.success
  enumerate :label, Labels, Labels.save
end

b) you have public underscored accessors for defined fields which will return the Enum definition as complex type

button = ButtonPrimary.new

button._type #=> ButtonType.primary
button._color #=> Color.success
button._label #=> Labels.save

c) you have the string representation of defined enumerated fields with str_ prefix

button = ButtonPrimary.new

button.str_type #=> 'primary'
button.str_color #=> 'success'
button.str_label #=> 'Zapisz'

d) you have boolean methods allowing to check which enum value has been defined or in other words: of what enum is the field in your PORO class

button = ButtonPrimary.new

button.button_type_primary? #=> true
button.button_type_secondary? #=> false
button.color_success? #=> true
button.color_danger? #=> false
button.label_save? #=> true
button.label_cancel? #=> false

Usage with ViewComponent

It's very convenient to use JustEnum with ViewComponent gem from Github You can define your enum classes:

module Enums
  class ButtonType < JustEnum::Base
    enum %i[primary secondary default success]
  end
end

Then extend your component classes with JustEnum::Enum

# frozen_string_literal: true

class ButtonPrimary < ViewComponent::Base
  extend JustEnum::Enum
  enumerate :type, ButtonType, ButtonType.primary
  
  attr_reader :label
  
  def initialize(label:)
    @label = label
  end
end

<%= render ButtonPrimary.new(label: "Start search") %>

Or you can go one step further and encapsulate enums in static methods

# frozen_string_literal: true

class Button < ViewComponent::Base
  include JustEnum::Enum

  class << self
    def primary(**args)
      args[:type_class] = %w[border-transparent text-white bg-indigo-600 hover:bg-indigo-700]
      new(**args, type: Enums::ButtonType.primary)
    end

    def secondary(**args)
      new(**args, type: Enums::ButtonType.secondary)
    end

    def default(**args)
      args[:type_class] = %w[bg-white border-gray-300 text-gray-700 hover:bg-gray-5]
      new(**args, type: Enums::ButtonType.default)
    end

    def success(**args)
      new(**args, type: Enums::ButtonType.success)
    end
  end

  attr_reader :label,

  def initialize(label:, type:)
    @type = args[:type] || Enums::ButtonType.default
    @label = args[:label]
  end
end

<%= render Button.default(label: "Cancel") %>
<%= render Button.primary(label: "Start search") %>

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rafpiek/just_enum.

just_enum