notifications-admin/app/assets/javascripts/preventDuplicateFormSubmissions.js

(function() {

  "use strict";

  let disableSubmitButtons = function(event) {

    var $submitButton = $(this).find(':submit');

    if ($submitButton.data('clicked') == 'true') {

      event.preventDefault();

    } else {

      $submitButton.data('clicked', 'true');

      if ($submitButton.is('[name="Send"], [name="Schedule"]')) {
        $submitButton.prop('disabled', true);

        setTimeout(() => {
          renableSubmitButton($submitButton);
        }, 10000);
      } else {
        setTimeout(renableSubmitButton($submitButton), 1500);
      }
    }
  };

  let renableSubmitButton = $submitButton => () => {

    $submitButton.data('clicked', '');
    $submitButton.prop('disabled', false);
  };

  $('form').on('submit', disableSubmitButtons);

})();