Calculate distance between two positions, given as object with LAT and LONG coordinates

calculateDistance.mjs

// Entirely based on answer given in: https://stackoverflow.com/questions/27928/calculate-distance-between-two-latitude-longitude-points-haversine-formula

export default function calculateDistance(position1, position2) {
	//lon1, lat1, lon2, lat2
	const R = 6371; // Radius of the earth in km
	const dLat = (position2.latitude - position1.latitude).toRad();
	const dLon = (position2.longitude - position1.longitude).toRad();
	const a =
		Math.sin(dLat / 2) * Math.sin(dLat / 2) +
		Math.cos(position1.latitude.toRad()) *
			Math.cos(position2.latitude.toRad()) *
			Math.sin(dLon / 2) *
			Math.sin(dLon / 2);
	const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
	const d = R * c; // Distance in km
	return d;
}