setsPortSpot, portSpot, setsChildPortSpot, and childPortSpot

can you please tell me when to use and how to apply setsPortSpot, portSpot, setsChildPortSpot, and childPortSpot.

I have gone through:
but was quite confuse about it.

Thanks in advance.

The layered layouts have a natural direction of growth. So they automatically set the Link.fromSpot and Link.toSpot to be in that direction. You can customize which spots to use by setting TreeLayout.portSpot and/or childPortSpot.

But sometimes you don’t want them to be set at all. You can turn off that behavior by setting TreeLayout.setsPortSpot and/or setsChildPortSpot to false, so that the fromSpot and/or toSpot of the port GraphObject take effect.