1 files changed, 46 insertions, 6 deletions

diff --git a/app/geometry.js b/app/geometry.js
index 421d90b..62236e0 100644
--- a/app/geometry.js
+++ b/app/geometry.js
@@ -10,7 +10,6 @@ const TOLERANCE = 1e-10;
 
 /**
  * Geographic bounds representation
- * @class
  */
 export class Bounds {
 	/**
@@ -26,6 +25,19 @@ export class Bounds {
 		this.maxY = maxY;
 	}
 
+	/**
+	 * Create a union of multiple Bounds objects to cover the combined area
+	 * @param {Bounds[]} boundsArray - Array of Bounds instances
+	 * @returns {Bounds} A new Bounds instance covering all input bounds
+	 */
+	static union(boundsArray) {
+		const minX = Math.min(...boundsArray.map((b) => b.minX));
+		const minY = Math.min(...boundsArray.map((b) => b.minY));
+		const maxX = Math.max(...boundsArray.map((b) => b.maxX));
+		const maxY = Math.max(...boundsArray.map((b) => b.maxY));
+		return new Bounds(minX, minY, maxX, maxY);
+	}
+
 	/** @returns {number} Width in degrees */
 	get width() {
 		return this.maxX - this.minX;
@@ -121,8 +133,8 @@ export class Geometry {
 
 	/**
 	 * Deserialize geometry from GeoJSON
-	 * @param {Object} geojson - GeoJSON geometry object
-	 * @returns {Geometry|null} Geometry instance or null
+	 * @param {{type: string, coordinates?: any, [key: string]: any}} geojson
+	 * @returns {Geometry|null}
 	 */
 	static fromGeoJSON(geojson) {
 		if (!geojson?.type) return null;
@@ -136,7 +148,7 @@ export class Geometry {
 			case "MultiLineString":
 				return MultiLineString.fromGeoJSON(geojson);
 			default:
-				throw new Error(`Unsupported geometry type: ${geojson.type}`);
+				throw new Error(`Invalid GeoJSON object: missing required 'type' property`);
 		}
 	}
 
@@ -253,8 +265,8 @@ export class Geometry {
 		const pointsB = Geometry.#geometryToPoints(b);
 
 		let minDistance = Infinity;
+		/** @type {[Point|null, Point|null]} */
 		let closestPair = [null, null];
-
 		for (const pointA of pointsA) {
 			for (const pointB of pointsB) {
 				const dist = Point.distance(pointA, pointB);
@@ -639,7 +651,17 @@ export class LineString extends Geometry {
 	}
 
 	/**
+	/**
 	 * Check if two segments intersect
+	 * @param {number} p0x
+	 * @param {number} p0y
+	 * @param {number} p1x
+	 * @param {number} p1y
+	 * @param {number} p2x
+	 * @param {number} p2y
+	 * @param {number} p3x
+	 * @param {number} p3y
+	 * @returns {boolean}
 	 */
 	static #segmentsIntersect(p0x, p0y, p1x, p1y, p2x, p2y, p3x, p3y) {
 		const s1x = p1x - p0x;
@@ -840,7 +862,17 @@ export class Polygon extends Geometry {
 	 * @returns {Polygon}
 	 */
 	static fromGeoJSON(geojson) {
-		return new Polygon(geojson.coordinates);
+		const rings = geojson.coordinates.map((ring /*: Coordinate[] */) => {
+			if (ring.length < 1) return ring;
+			const first = ring[0];
+			const last = ring[ring.length - 1];
+			if (first[0] !== last[0] || first[1] !== last[1]) {
+				// Append first coordinate to the end if not closed
+				return [...ring, first];
+			}
+			return ring;
+		});
+		return new Polygon(rings);
 	}
 
 	/**
@@ -892,6 +924,10 @@ export class Feature {
 	 * @param {Object} geojson - GeoJSON feature
 	 * @returns {Feature|null}
 	 */
+	/**
+	 * @param {{geometry: object, properties?: object, id?: string|number}} geojson
+	 * @returns {Feature|null}
+	 */
 	static fromGeoJSON(geojson) {
 		if (!geojson?.geometry) return null;
 
@@ -928,6 +964,10 @@ export class Collection {
 	 * @param {Object} geojson - GeoJSON collection
 	 * @returns {Collection}
 	 */
+	/**
+	 * @param {{features?: any[]}} geojson
+	 * @returns {Collection}
+	 */
 	static fromGeoJSON(geojson) {
 		const features = (geojson.features ?? []).map(Feature.fromGeoJSON).filter(Boolean);