a wrapped children data operator that functions as a children operator
When creating a Hierarchy with a children data operator, the corresponding Hierarchy#children will be wrapped in this.
get children from a node
the datum to get children of
the index with which the data was encountered
children - all the children data of this node, or undefined if there are no children
the wrapped children data operator
a wrapped children data operator that functions as a children operator
When creating a Hierarchy with a children data operator, the corresponding Hierarchy#children will be wrapped in this.