MetacatUI

I checked in a geohash JS library that seems to do what we need for MetacatUI -

decode geohashes, 
encode lat/lon pairs
decode a geohash value into a lat/long bounding box
get an array of geohashes that are contained within a lat,long bounding box
get an array of geohashes that are adjacent to a specified geohash
etc.

https://github.com/sunng87/node-geohash