Converted turf-mask to Typescript and added support for geometry parameters

packages/turf-mask/README.md

@@ -4,36 +4,35 @@
 
 ## mask
 
-Takes any type of [polygon][1] and an optional mask and returns a [polygon][1] exterior ring with holes.
+Takes polygons or multipolygons and an optional mask, and returns an exterior
+ring polygon with holes.
 
 ### Parameters
 
-*   `polygon` **([FeatureCollection][2] | [Feature][3]<([Polygon][4] | [MultiPolygon][5])>)** GeoJSON Polygon used as interior rings or holes.
-*   `mask` **[Feature][3]<[Polygon][4]>?** GeoJSON Polygon used as the exterior ring (if undefined, the world extent is used)
+*   `polygon` **([Polygon][1] | [MultiPolygon][2] | [Feature][3]<([Polygon][1] | [MultiPolygon][2])> | [FeatureCollection][4]<([Polygon][1] | [MultiPolygon][2])>)** GeoJSON polygon used as interior rings or holes
+*   `mask` **([Polygon][1] | [Feature][3]<[Polygon][1]>)?** GeoJSON polygon used as the exterior ring (if undefined, the world extent is used)
 
 ### Examples
 
 ```javascript
-var polygon = turf.polygon([[[112, -21], [116, -36], [146, -39], [153, -24], [133, -10], [112, -21]]]);
-var mask = turf.polygon([[[90, -55], [170, -55], [170, 10], [90, 10], [90, -55]]]);
+const polygon = turf.polygon([[[112, -21], [116, -36], [146, -39], [153, -24], [133, -10], [112, -21]]]);
+const mask = turf.polygon([[[90, -55], [170, -55], [170, 10], [90, 10], [90, -55]]]);
 
-var masked = turf.mask(polygon, mask);
+const masked = turf.mask(polygon, mask);
 
 //addToMap
-var addToMap = [masked]
+const addToMap = [masked]
 ```
 
-Returns **[Feature][3]<[Polygon][4]>** Masked Polygon (exterior ring with holes).
+Returns **[Feature][3]<[Polygon][1]>** Masked Polygon (exterior ring with holes).
 
 [1]: https://tools.ietf.org/html/rfc7946#section-3.1.6
 
-[2]: https://tools.ietf.org/html/rfc7946#section-3.3
+[2]: https://tools.ietf.org/html/rfc7946#section-3.1.7
 
 [3]: https://tools.ietf.org/html/rfc7946#section-3.2
 
-[4]: https://tools.ietf.org/html/rfc7946#section-3.1.6
-
-[5]: https://tools.ietf.org/html/rfc7946#section-3.1.7
+[4]: https://tools.ietf.org/html/rfc7946#section-3.3
 
 <!-- This file is automatically generated. Please don't edit it directly. If you find an error, edit the source file of the module in question (likely index.js or index.ts), and re-run "yarn docs" from the root of the turf project. -->
 

packages/turf-mask/bench.ts

@@ -1,8 +1,9 @@
+import { Feature, FeatureCollection, Polygon, MultiPolygon } from "geojson";
 import fs from "fs";
 import path from "path";
 import { fileURLToPath } from "url";
 import { loadJsonFileSync } from "load-json-file";
-import Benchmark from "benchmark";
+import Benchmark, { Event } from "benchmark";
 import { mask as turfMask } from "./index.js";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
@@ -17,21 +18,23 @@ const directories = {
 let fixtures = fs.readdirSync(directories.in).map((filename) => {
   return {
     name: path.parse(filename).name,
-    geojson: loadJsonFileSync(path.join(directories.in, filename)),
+    geojson: loadJsonFileSync(
+      path.join(directories.in, filename)
+    ) as FeatureCollection<Polygon | MultiPolygon>,
   };
 });
 
 for (const { name, geojson } of fixtures) {
   const [polygon, masking] = geojson.features;
-  suite.add(name, () => turfMask(polygon, masking));
+  suite.add(name, () => turfMask(polygon, masking as Feature<Polygon>));
 }
 
 // basic x 4,627 ops/sec ±25.23% (21 runs sampled)
 // mask-outside x 3,892 ops/sec ±34.80% (15 runs sampled)
 // multi-polygon x 5,837 ops/sec ±3.03% (91 runs sampled)
 // overlapping x 22,326 ops/sec ±1.34% (90 runs sampled)
 suite
-  .on("cycle", (event) => {
+  .on("cycle", (event: Event) => {
     console.log(String(event.target));
   })
   .run();

packages/turf-mask/index.ts

@@ -0,0 +1,118 @@
+import {
+  Feature,
+  FeatureCollection,
+  Polygon,
+  Position,
+  MultiPolygon,
+} from "geojson";
+import { polygon as createPolygon, multiPolygon } from "@turf/helpers";
+import polygonClipping, { Geom } from "polygon-clipping";
+
+/**
+ * Takes polygons or multipolygons and an optional mask, and returns an exterior
+ * ring polygon with holes.
+ *
+ * @name mask
+ * @param {Polygon|MultiPolygon|Feature<Polygon|MultiPolygon>|FeatureCollection<Polygon|MultiPolygon>} polygon GeoJSON polygon used as interior rings or holes
+ * @param {Polygon|Feature<Polygon>} [mask] GeoJSON polygon used as the exterior ring (if undefined, the world extent is used)
+ * @returns {Feature<Polygon>} Masked Polygon (exterior ring with holes).
+ * @example
+ * const polygon = turf.polygon([[[112, -21], [116, -36], [146, -39], [153, -24], [133, -10], [112, -21]]]);
+ * const mask = turf.polygon([[[90, -55], [170, -55], [170, 10], [90, 10], [90, -55]]]);
+ *
+ * const masked = turf.mask(polygon, mask);
+ *
+ * //addToMap
+ * const addToMap = [masked]
+ */
+function mask<T extends Polygon | MultiPolygon>(
+  polygon: T | Feature<T> | FeatureCollection<T>,
+  mask?: Polygon | Feature<Polygon>
+): Feature<Polygon> {
+  // Define mask
+  const maskPolygon = createMask(mask);
+
+  let polygonOuters = null;
+  if (polygon.type === "FeatureCollection") {
+    polygonOuters = unionFc(polygon);
+  } else if (polygon.type === "Feature") {
+    // Need to cast below as Position[][] isn't quite as strict as Geom, even
+    // though they should be equivalent.
+    polygonOuters = createGeomFromPolygonClippingOutput(
+      polygonClipping.union(polygon.geometry.coordinates as Geom)
+    );
+  } else {
+    // Geometry
+    // Need to cast below as Position[][] isn't quite as strict as Geom, even
+    // though they should be equivalent.
+    polygonOuters = createGeomFromPolygonClippingOutput(
+      polygonClipping.union(polygon.coordinates as Geom)
+    );
+  }
+
+  polygonOuters.geometry.coordinates.forEach(function (contour) {
+    maskPolygon.geometry.coordinates.push(contour[0]);
+  });
+
+  return maskPolygon;
+}
+
+function unionFc(fc: FeatureCollection<Polygon | MultiPolygon>) {
+  // Need to cast below as Position[][] isn't quite as strict as Geom, even
+  // though they should be equivalent.
+
+  // Stick with apply() below as spread operator degrades performance. Have
+  // to disable prefer-spread lint rule though.
+  /* eslint-disable prefer-spread */
+  const unioned =
+    fc.features.length === 2
+      ? polygonClipping.union(
+          fc.features[0].geometry.coordinates as Geom,
+          fc.features[1].geometry.coordinates as Geom
+        )
+      : polygonClipping.union.apply(
+          polygonClipping,
+          fc.features.map(function (f) {
+            return f.geometry.coordinates;
+          }) as [Geom, ...Geom[]]
+        );
+  /* eslint-enable */
+  return createGeomFromPolygonClippingOutput(unioned);
+}
+
+function createGeomFromPolygonClippingOutput(unioned: Position[][][]) {
+  return multiPolygon(unioned);
+}
+
+/**
+ * Create Mask Coordinates
+ *
+ * @private
+ * @param {Feature<Polygon>} [mask] default to world if undefined
+ * @returns {Feature<Polygon>} mask as a polygon
+ */
+function createMask(mask: Feature<Polygon> | Polygon | undefined) {
+  const world = [
+    [
+      [180, 90],
+      [-180, 90],
+      [-180, -90],
+      [180, -90],
+      [180, 90],
+    ],
+  ];
+  let coordinates = world;
+  if (mask) {
+    if (mask.type === "Feature") {
+      // polygon feature
+      coordinates = mask.geometry.coordinates;
+    } else {
+      // polygon geometry
+      coordinates = mask.coordinates;
+    }
+  }
+  return createPolygon(coordinates);
+}
+
+export { mask };
+export default mask;

packages/turf-mask/package.json

@@ -60,10 +60,13 @@
     "tape": "^5.7.2",
     "tsup": "^8.0.1",
     "tsx": "^4.6.2",
+    "typescript": "^5.2.2",
     "write-json-file": "^5.0.0"
   },
   "dependencies": {
     "@turf/helpers": "workspace:^",
-    "polygon-clipping": "^0.15.3"
+    "@types/geojson": "7946.0.8",
+    "polygon-clipping": "^0.15.3",
+    "tslib": "^2.6.2"
   }
 }