route.ts

async function routeBetween(
    directionSvc: import("./modern_services").DirectionService,
    parks: Park[]
) {
    const waypoints: google.maps.DirectionsWaypoint[] = parks.map((p) => ({ location: p.place }));

    const req: google.maps.DirectionsRequest = {
        origin: 'New York Penn Station',
        destination: 'New York Penn Station',
        optimizeWaypoints: true,
        travelMode: google.maps.TravelMode.WALKING,
        waypoints: waypoints,
    };
    return directionSvc.routeAsync(req).then((res) => {
        const seconds = res.routes[0].legs.reduce((a, b) => (a + b.duration.value), 0);
        return <TripSummary>{
            parks: res.routes[0].waypoint_order.map(i => parks[i]),
            duration: seconds,
            path: res.routes[0].overview_path,
        };
    });
}