code: function (formattedData, model) {
      var parts = formattedData.trim().split("@");
      if (parts.length === 2 && _.all(parts)) {
        return formattedData;
      }
    }
docs: Return the input if it is a string that contains an '@' character and if
  the strings before and after '@' are non-empty. If the input does not
  validate, `undefined` is returned.
  
  @member Backgrid.EmailFormatter
  @param {*} formattedData
  @param {Backbone.Model} model Used for more complicated formatting
  @return {string|undefined}