hb_ajax_rails_form_errors

// in the Gemfile
gem 'handlebars_assets'

// in hb_helpers.js.coffee
Handlebars.registerHelper 'humanize', (str) ->
  str.replace(/_/g, ' ')
  
// application.js
//= require jquery
//= require jquery_ujs
//= require turbolinks
//= require handlebars.runtime
//= require hb_helpers
//= require_tree ./templates
//= require_tree .

//coffescript file i.e. form_errors.js.coffee
window.FormErrors = do ->
  # Private methods
  _displayErrors = (container, response) ->
    compiledView = HandlebarsTemplates['shared/form_errors'](response)
    container.html(compiledView)
    container.show()

  # Public methods
  init: (params={}) ->
    onError = params.onError
    onSuccess = params.onSuccess
    form = $("##{params.formId}")
    errorsContainer = $("##{params.errorsContainerId}")

    form.on("ajax:success", (e, data, status, xhr) ->
      onSuccess(data) if (typeof onSuccess is 'function')
    ).on("ajax:error", (e, xhr, status, error) ->
      onError(xhr.responseJSON) if (typeof onError is 'function')
      _displayErrors(errorsContainer, xhr.responseJSON)
    )
    
 // using handlebars template
 // i.e. /templates/form_errors.hbs
 <ul>
{{#each errors as |msgs attr|}}
  {{#each msgs as |msg|}}
    <li>{{humanize attr}}: {{msg}}</li>
  {{/each}}
{{/each}}

// in the view .html.erb
<% content_for :bottom_js do %>
  <script type="text/javascript">
    $(function(){
      FormErrors.init({
        formId: "activate-account-form",
        errorsContainerId: "form-errors",
        onSuccess: function(data) {
          window.location.href = "<%= orders_url %>"
        }
      });
    });
  </script>
<% end %>