Distance between two gps locations

dist2GPS.ts

const numToRad = (num) => (num * Math.PI) / 180;

export const getDistFrom2GpsLocations = ({ lat1, long1, lat2, long2 }) => {
  lat1 = parseFloat(lat1);
  long1 = parseFloat(long1);
  lat2 = parseFloat(lat2);
  long2 = parseFloat(long2);

  const R = 6371e3;
  const φ1 = numToRad(lat1);
  const φ2 = numToRad(lat2);
  const Δφ = numToRad(lat2 - lat1);
  const Δλ = numToRad(long2 - long1);

  const a =
    Math.sin(Δφ / 2) * Math.sin(Δφ / 2) +
    Math.cos(φ1) * Math.cos(φ2) * Math.sin(Δλ / 2) * Math.sin(Δλ / 2);
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

  return parseInt(String(R * c), 10); //meters
  // return R * c * 0.000621371192; // miles;
};