calcDistanceBetweenTwoPoints.js

function calcDistanceInMetresBetweenTwoPoints(Point1, Point2) {
  const EARTH_RADIUS = 6371e3; // 6,371,000 metres

  const latitude1 = (Point1.lat * Math.PI) / 180;
  const latitude2 = (Point2.lat * Math.PI) / 180;

  const deltaLatitude = ((Point2.lat - Point1.lat) * Math.PI) / 180;
  const deltaLongitude = ((Point2.lon - Point1.lon) * Math.PI) / 180;

  const angle =
    Math.sin(deltaLatitude / 2) * Math.sin(deltaLatitude / 2) +
    Math.cos(latitude1) * Math.cos(latitude2) * Math.sin(deltaLongitude / 2) * Math.sin(deltaLongitude / 2);

  const theta = 2 * Math.atan2(Math.sqrt(angle), Math.sqrt(1 - angle));

  const distance = EARTH_RADIUS * theta;

  return Math.round(distance * 100) / 100; // distance in metres, rounded up!
}

// Test
const PointA = { lat: -33.84887785692942, lon: 151.2106926524797 };
const PointB = { lat: -33.85469551244261, lon: 151.22570778047384 };
const result = calcDistanceInMetresBetweenTwoPoints(PointA, PointB);

console.log(result); // 1530.05 metres

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