code: function shallowValueGetter(obj, fieldName) {
      if (obj == null)
          return '';
      if (!obj || !fieldName)
          return obj;
      var value = obj[fieldName];
      if (value == null)
          return '';
      return value;
  }
docs: Returns the value of a field.
  (more efficient than deepValueGetter)
  @param obj object containing the field
  @param fieldName field name string
  @returns {any}