Remote Execution Fourth Example

example04.js

const degsToRads = (deg) => Math.PI / 180 * deg;
const haversine = (origin, dest) => Math.acos(
  Math.sin(degsToRads(origin.lat)) * Math.sin(degsToRads(dest.lat)) +
  Math.cos(degsToRads(origin.lat)) * Math.cos(degsToRads(dest.lat)) * Math.cos(degsToRads(dest.lng - origin.lng))
);
let bbox = 0.1;
for (; (await query(`
  select count(*) from notablePlaces
  where notablePlaces.lat < $0 + $2
  and notablePlaces.lat > $0 - $2
  and notablePlaces.lng < $1 + $2
  and notablePlaces.lng > $1 - $2
`, [trip.destLat, trip.destLng, bbox]))[0].count < 4; bbox *= 2) {}
const closeNotablePlaces = await query(`
  select * from notablePlaces
  where notablePlaces.lat < $0 + $2
  and notablePlaces.lat > $0 - $2
  and notablePlaces.lng < $1 + $2
  and notablePlaces.lng > $1 - $2
`, [trip.destLat, trip.destLng, bbox]);
const relevantPlaces = closeNotablePlaces
  .map((p) => ({
    name: p.name,
    img: p.img,
    desc: p.desc,
    distance: haversine({
      lat: p.lat,
      lng: p.lng,
    }, {
      lat: trip.destLat,
      lng: trip.destLng,
    }),
  }))
  .sort((a, b) => b.distance - a.distance)
  .slice(0, 4);