QueryResultRowGetExpressionResultT(String) - метод

public T GetExpressionResult<T>(
	string expressionAlias
)
where T : SingleValueProperty

Public Function GetExpressionResult(Of T As SingleValueProperty) ( 
	expressionAlias As String
) As T

Dim instance As QueryResultRow
Dim expressionAlias As String
Dim returnValue As T

returnValue = instance.GetExpressionResult(expressionAlias)

JScript не поддерживает универсальные типы и методы.