haversine, get closest station

getClosestStation.js

export const getClosestStation = (lat, lng, data) => {
    const results = [];
    data.forEach(element => {
        const _dummy = haversine(lat, lng, element.latitude, element.longitude);
        results.push({ ...element, distance: _dummy });
    });
    const min = Math.min.apply(
        null,
        results.map(item => item.distance),
    );
    return results.filter(elem => elem.distance === min)[0];
};

getCoordinatesInRangePickupDropoff.js

export const getCoordinatesInRangePickupDropoff = (pickup, dropoff, routePolylineSelected) => {
    if (_.isEmpty(routePolylineSelected)) {
        return null;
    }

    const routePolylineDecoded = window.google.maps.geometry.encoding.decodePath(routePolylineSelected);
    if (_.isEmpty(routePolylineDecoded)) {
        return [];
    }
    const startIndex = routePolylineDecoded.findIndex(item => {
        return haversine(item.lat(), item.lng(), pickup.latitude, pickup.longitude) === 0;
    });
    const endIndex = routePolylineDecoded.findIndex(item => haversine(item.lat(), item.lng(), dropoff.latitude, dropoff.longitude) === 0);
    return routePolylineDecoded.filter((_item, index) => index > startIndex && index < endIndex);
};

haversine.js

export const haversine = (lat1, lng1, lat2, lng2) => {
    const [pi, asin, sin, cos, sqrt, pow, round] = ['PI', 'asin', 'sin', 'cos', 'sqrt', 'pow', 'round'].map(k => Math[k]);
    const [rlat1, rlat2, rlng1, rlng2] = [lat1, lat2, lng1, lng2].map(x => (x / 180) * pi);
    const dLat = rlat2 - rlat1;
    const dLon = rlng2 - rlng1;
    const radius = 6372.8; // km
    return round(radius * 2 * asin(sqrt(pow(sin(dLat / 2), 2) + pow(sin(dLon / 2), 2) * cos(rlat1) * cos(rlat2))) * 100) / 100;
};