grabowski
fe89bb2b1c
Multi-user trip planning web app in a single Docker container. Mullvad-style token accounts, trip sharing via join codes, day-by-day calendar with typed entries (activity, hotel, travel, flight, rental car, immigration, note), multi-leg flight segments with bundled IATA airport dataset, Leaflet/OSM map with per-leg great-circle km (air vs ground), rough km-driven vs rental included-km comparison, cost splitting with settle-up suggestions, flip-clock departure countdown. Node 20 + Express + SQLite (WAL, additive migrations), vanilla JS SPA, 44 API tests.
18 lines
492 B
JavaScript
18 lines
492 B
JavaScript
// Great-circle distance between two lat/lng points, in kilometers.
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const EARTH_RADIUS_KM = 6371;
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function toRad(deg) {
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return (deg * Math.PI) / 180;
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}
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export function haversineKm(lat1, lng1, lat2, lng2) {
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const dLat = toRad(lat2 - lat1);
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const dLng = toRad(lng2 - lng1);
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const a =
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Math.sin(dLat / 2) ** 2 +
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Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) * Math.sin(dLng / 2) ** 2;
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const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
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return EARTH_RADIUS_KM * c;
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}
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