I was applied the tree layout to the diagram.And the node are connected in the reverse direction
Actual OutPut:

Expected Out Put:

I was applied the tree layout to the diagram.And the node are connected in the reverse direction
Actual OutPut:

Expected Out Put:

By default GoJS thinks trees are composed of nodes connected by links that go from the parent to the children.
Set Diagram | GoJS API to false when you initialize your diagram:
isTreePathToChildren: false,