mbostock/d3 — pull request #1063 by mbostock (2013-02-06 18:20:28+00:00)
Title: Sort null nodes at the end.

Previously, null nodes were passed to the comparator and were indistinguishable
from non-null nodes with no bound data. For consistency with other selection
operators that skip null nodes, it seems preferrable to put null nodes at the
end of the selection rather than passing them to the comparator. Fixes #881.