The form builder is suitable for use with any Rails application that uses the GOV.UK Design System. If you’re starting from scratch, the easiest way to hit the ground running is to use the DfE Rails Boilerplate.
Once your application is working, simply add the following line to your
Gemfile and run
Now we just need to tell Rails which form builder to use. We can do
this globally by amending the
class ApplicationController < ActionController::Base default_form_builder GOVUKDesignSystemFormBuilder::FormBuilder end
Alternatively, if you’re not quite ready to make the full switch, you can specify the form builder on a form-by-form basis. All examples in this guide are written using Slim but the form builder works just as well with ERB or Haml.
= form_for @some_object, builder: GOVUKDesignSystemFormBuilder::FormBuilder do |f| = f.govuk_text_field :name = f.govuk_phone_field :telephone_number
If you made it this far and everything’s working, well done!