location.js

function pythagoreanDistanceBetweenPoints(lat1, lon1, lat2, lon2) {
  const R = 6371e3;
  const x = (lon2-lon1) * Math.cos((lat1+lat2)/2);
  const y = (lat2-lat1);
  const d = Math.sqrt(x*x + y*y) * R;
  return d;
}