Get utm zone from DD In javascript and Ol3

Question

How find current utm zone from lon lat position (from mapcenter for example) ?

I need to determine which utm zone currently is from my position.

Answer 1

function getUtmZoneFromPosition(lon,lat) {
  return (Math.floor((lon + 180) / 6) % 60) + 1;
}

and in ol3 use function this way

function getCurrentUtmZone() {
    var position = ol.proj.transform(mapObj.getView().getCenter(), mapObj.getView().getProjection(), "EPSG:4326");
    return getUtmZoneFromPosition(position[0]);
}

var currentZone=getCurrentUtmZone();

Thanks to Determining UTM zone (to convert) from longitude/latitude