gpx2kml
Use in terminal
$ npm i -g gpx2kml
$ gpx2kml my_first_track.gpx -o output.kml
or
$ cat my_first_track.gpx | gpx2kml > output.kml
Batch conversion
$ gpx2kml *.gpx
Use as package
import gpx2kml from 'gpx2kml';
const gpx_raw = `<?xml version="1.0" ... </gpx>`;
const kml_raw = gpx2kml(gpx_raw);