best-route-problem.js

const positions = {
  Aman: {
    latitude: 0,
    longitude: 0,
  },
  R1: {
    latitude: 0,
    longitude: 0,
  },
  R2: {
    latitude: 0,
    longitude: 0,
  },
  C1: {
    latitude: 0,
    longitude: 0,
  },
  C2: {
    latitude: 0,
    longitude: 0,
  },
};

const possibleRoutes = [
  ['Aman', 'R1', 'C1', 'R2', 'C2'],
  ['Aman', 'R1', 'R2', 'C1', 'C2'],
  ['Aman', 'R1', 'R2', 'C2', 'C1'],
  ['Aman', 'R2', 'C2', 'R1', 'C1'],
  ['Aman', 'R2', 'R1', 'C2', 'C1'],
  ['Aman', 'R2', 'R1', 'C1', 'C2'],
];

/**
 * @description Convert angle from degree to radian
 * @param {Number} deg - Angle in degree
 *
 * @returns {Number} Angle in Radian
 */
const deg2rad = deg => deg * (Math.PI / 180);

/**
 * @description Find distance between two geo locations using Haversine Formula
 * @param {Number} lat1  - Latitude 1
 * @param {Number} lon1  - Longitude 1
 * @param {Number} lat2  - Latitude 2
 * @param {Number} lon2  - Longitude 2
 *
 * @returns {Number} Distance
 */
const findDistance = (lat1, lon1, lat2, lon2) => {
  const R = 6371000; // Earth's radius in meteres
  const dLat = deg2rad(lat2 - lat1);
  const dLon = deg2rad(lon2 - lon1);
  const a =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.cos(deg2rad(lat1)) *
      Math.cos(deg2rad(lat2)) *
      Math.sin(dLon / 2) *
      Math.sin(dLon / 2);
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
  return R * c;
};

/**
 * @description Find best route for the delivery
 *
 * @returns {Array} Route to follow
 */
const getBestRoute = () => {
  const distances = possibleRoutes.map(route => {
    let totalDistance = 0;
    for (let i = 0; i < route.length - 1; i++) {
      const firstLocation = route[i];
      const secondLocation = route[i + 1];
      const distance = findDistance(
        positions[firstLocation].latitude,
        positions[firstLocation].longitude,
        positions[secondLocation].latitude,
        positions[secondLocation].longitude
      );
      totalDistance += distance;
    }
    return totalDistance;
  });
  const minDistance = Math.min(...distances);
  const bestRoute = possibleRoutes[distances.indexOf(minDistance)];
  return bestRoute;
};