D3.js packed circle layout - how to adjust child radius

Question

I am currently useing d3\'s packed cicle layout(this) and have noticed that when a parent only has one child, the radius of the child is the same as the parents.

Is

Answer 1

I haven't looked at v3 of D3, but v4 has pack.padding() method that you can specify the amount of padding to include.

See the example image, the circle on the right is a solo child.