voronoi.cellPolygons skips null cells, and doesn’t report the cell’s index.

[mbostock]

As a result, it’s not very useful: you can’t tell which cell polygon corresponds to which site.

Perhaps it could just assign cell.index on the yielded cell?

[Fil]

Yes it's a problem. The README says "Returns an iterable over the polygons for each cell, in order" and was written after e641963, so the situation is a bit fuzzy. I'm not sure why you would want to skip null polygons, but the cell.index solution is fine.

[mbostock]

Hmm. Yielding null might be fine, too?

(I’m also not really sure it’s useful that these methods are generators rather than returning an array or sparse array…)

[Fil]

Yielding null is fine IMO, but reverting to it might break someone's assumption (though not the documentation). I have no preference. Generators are nice to look at in observable, but I don't know if there's a practical use, since we can in any case use voronoi.cellPolygon(i) to enumerate.