code: function valueIsNullForValidator(value, validatorName) {
    if (value === null || value === CONSTANT.NULL || typeof value === 'undefined') {
      return true;
    }
  
    if (value === '' && VALIDATOR_CONSIDERS_EMPTY_STRING_NULL[validatorName]) {
      return true;
    }
  
    return false;
  }
docs: Check if a given value is a null for a validator
  @param {String} value - value to be checked if null
  @param {String} validatorName - the name of the current validation function
  @return {Boolean} whether or not the current value is null