protected function _calculateType($field)
    {
        $field = $field instanceof IdentifierExpression ? $field->getIdentifier() : $field;
        if (is_string($field)) {
            return $this->getTypeMap()->type($field);
        }

        return null;
    }
protected function _calculateType($field)
    {
        $field = $field instanceof IdentifierExpression ? $field->getIdentifier() : $field;
        if (is_string($field)) {
            return $this->getTypeMap()->type($field);
        }

        return null;
    }
protected function _calculateType ( $ field ) { $ field = $ field instanceof IdentifierExpression ? $ field -> getIdentifier ( ) : $ field ; if ( is_string ( $ field ) ) { return $ this -> getTypeMap ( ) -> type ( $ field ) ; } return null ; }
Returns the type name for the passed field if it was stored in the typeMap

@param string|\Cake\Database\Expression\IdentifierExpression $field The field name to get a type for.
@return string|null The computed type or null, if the type is unknown.
Returns the type name for the passed field if it was stored in the typeMap