Sorry, I just saw your last reply.
I think I see the problem. The inventoryDetail is not supposed to be an array. It can be null, but if it’s not, it should be an object. The object contains an array at the subpath inventoryAssignmentList.inventoryAssignment. So I think you need to handle it being null by providing a default value that adheres to that structure, using an expression like this:
sl.ensureArray($.get(‘tranSales:inventoryDetail’, {'inventoryAssignmentList': {'inventoryAssignment': []}))
I’m not certain that’s right, but give it a shot.