Voronoi where each site is a segment instead of a point.

[HDv2b]

I have a map with one or more polylines, and want to know the segment that is closest to the cursor. I've successfully done this in another library (https://github.com/Voxel8/pyvoronoi), however (besides preferring to be using JS), I'm seeing that on larger scales the voronoi chart is being warped by the earth's curvature, hence this d3-geo-voronoi seems worth a try. Problem is my understanding of geometry isn't sufficient enough to bridge the gap between generating from points to generating from segments. Does anyone please have some advice? Thanks.