DiegoSalazar / presenter_object

Presenter object base class

PresenterObject

This is a simple presenter base class you can use to create model specific presenters.

Installation

Add this line to your application's Gemfile:

gem 'presenter_object'

And then execute:

$ bundle

Or install it yourself as:

$ gem install presenter_object

Usage

Given a model class:

class User < ActiveRecord::Base
   validates :first_name, presence: true # just to show one of the attributes of this model
end

Create a subclass such as:

class UserPresenter < PresenterObject::Base
  presents :user

  def formatted_phone_number
    I18n.l phone_number, format: :fancy
  end  
end

Then wrap a model instance:

@user = UserPresenter.new User.find(params[:id])

The @user presenter object can be used as if it were the model object. Then, just place all presentation methods in the presenter class and call them from the views.

@user.class # => User
@user.respond_to? :first_name # => true
@user.formatted_phone_number # => "[phone]"

Collection Presenter

You can also wrap whole collections of objects at once. Create a collection presenter:

class UserCollectionPresenter < PresenterObject::Collection
  def render_table
    each do |object|
      # object is now wrapped in its presenter
    end
  end
end

Instantiate the collection presenter by passing in an object collection and an optional view_context:

@user_collection = UserCollectionPresenter.new User.all, view_context
@user_collection.render_table

The @user_collection instance is an Enumerable and will lazily wrap each object when you iterate over the collection.

Development

After checking out the repo, run bin/setup to install dependencies. 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 tags, and push the .gem file to rubygems.org.

Contributing

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