text: var request;
  
  
  module.exports = {
      /*
       * 
       */
      calc: function (equation) {
          var d = $.Deferred();
  
          if (request) {
              request.abort();
          }
          request = $.ajax({
              cache: false,
              data: {equation: equation},
              method: 'GET',
              url: window.location.pathname .replace(/\/+$/, '') + '/calculator',
              dataType: 'json'
          }).done(function (response) {
              d.resolve(response);
          }).fail(function (response) {
              d.reject({
                  success: false,
                  data: response});
          });
          return d.promise();
      }
  }