Ruby on Rails - Simple Form AJAX Validations(works with bootstrap)

simple_form_ajax_validations.coffee

removeValidations = (scope) ->
  $(scope).find('.has-error .help-block').remove()
  $(scope).find('.has-error').removeClass('has-error')

showValidations = (errors, scope = '') ->
  for field, fieldErrors of errors
    wrapper = wrapperForField(field, scope)
    wrapper.addClass('has-error')
    for error in fieldErrors
      wrapper.append("<div class='help-block'>#{error}</div>")

wrapperForField = (field, scope = '') ->
  scope += ' ' if scope[0]
  $("#{scope}[name*='[#{field}]']").closest('.form-group')

usage.coffee

# In error callback:

error: (response) ->
  errors = response.responseJSON
  removeValidations('.form-selector')
  showValidations(errors, '.form-selector')