The geodesic routines in GeographicLib have been implemented inJavaScript library. See https://geographiclib.sourceforge.io/html/jsWilliam Wall <wallw@users.sourceforge.net> has posted a method ofautomatically translating the C++ code into JavaScript https://sourceforge.net/p/geographiclib/discussion/1026620/thread/f6f6b9ff/This will let you use other capabilities of GeographicLib in JavaScript.This is implemented in OpenSphere ASM https://github.com/ngageoint/opensphere-asm