Initial commit

node_modules/@maplibre/geojson-vt/src/feature.ts

@@ -0,0 +1,71 @@
+import type { GeoJSONVTInternalFeature, GeoJSONVTInternalLineStringFeature, GeoJSONVTInternalMultiLineStringFeature, GeoJSONVTInternalMultiPointFeature, GeoJSONVTInternalMultiPolygonFeature, GeoJSONVTInternalPointFeature, GeoJSONVTInternalPolygonFeature } from "./definitions";
+
+type FeatureTypeMap = {
+    Point: GeoJSONVTInternalPointFeature["geometry"];
+    MultiPoint: GeoJSONVTInternalMultiPointFeature["geometry"];
+    LineString: GeoJSONVTInternalLineStringFeature["geometry"];
+    MultiLineString: GeoJSONVTInternalMultiLineStringFeature["geometry"];
+    Polygon: GeoJSONVTInternalPolygonFeature["geometry"];
+    MultiPolygon: GeoJSONVTInternalMultiPolygonFeature["geometry"];
+};
+
+/**
+ * 
+ * @param id - the feature's ID
+ * @param type - the feature's type
+ * @param geom - the feature's geometry
+ * @param tags - the feature's properties
+ * @returns the created feature
+ */
+export function createFeature<T extends GeoJSONVTInternalFeature["type"]>(id: number | string | undefined, type: T, geom: FeatureTypeMap[T], tags: GeoJSON.GeoJsonProperties): GeoJSONVTInternalFeature {
+    // This is mostly for TypeScript type narrowing
+    const data = { type, geom } as { [K in GeoJSONVTInternalFeature["type"]]: { type: K, geom: FeatureTypeMap[K] } }[GeoJSONVTInternalFeature["type"]];
+
+    const feature = {
+        id: id == null ? null : id,
+        type: data.type,
+        geometry: data.geom,
+        tags,
+        minX: Infinity,
+        minY: Infinity,
+        maxX: -Infinity,
+        maxY: -Infinity
+    } as GeoJSONVTInternalFeature;
+
+    switch (data.type) {
+        case 'Point':
+        case 'MultiPoint':
+        case 'LineString':
+            calcLineBBox(feature, data.geom);
+            break;
+
+        case 'Polygon':
+            // the outer ring (ie [0]) contains all inner rings
+            calcLineBBox(feature, data.geom[0]);
+            break;
+
+        case 'MultiLineString':
+            for (const line of data.geom) {
+                calcLineBBox(feature, line);
+            }
+            break;
+
+        case 'MultiPolygon':
+            for (const polygon of data.geom) {
+                // the outer ring (ie [0]) contains all inner rings
+                calcLineBBox(feature, polygon[0]);
+            }
+            break;
+    }
+
+    return feature;
+}
+
+function calcLineBBox(feature: GeoJSONVTInternalFeature, geom: number[]) {
+    for (let i = 0; i < geom.length; i += 3) {
+        feature.minX = Math.min(feature.minX, geom[i]);
+        feature.minY = Math.min(feature.minY, geom[i + 1]);
+        feature.maxX = Math.max(feature.maxX, geom[i]);
+        feature.maxY = Math.max(feature.maxY, geom[i + 1]);
+    }
+}