Distance between points simplified

calculate geometric euclidean distance

getDistanceFromLatLonInM(lat1, lon1, lat2, lon2) {
  var deg2rad = deg => deg * 0.017453293;
  var a =
    Math.pow(Math.sin(deg2rad(lat2 - lat1) / 2), 2) +
    Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *
    Math.pow(Math.sin(deg2rad(lon2 - lon1) / 2), 2);
  return 12742000 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
}

is this in meters or miles?

Meters, as it says in the name, conforming to Si.

meters is usually lowercased, also line 2 should be 0.017453293, not 0,017453293

meters is usually lowercased, also line 2 should be 0.017453293, not 0,017453293

In the function name it goes as a separate word "Meters" that's why it is a capital letter. Also I have no idea how a comma ended up in the number, I fixed it thanks for the pointer.