Converted turf-tesselate to Typescript

packages/turf-tesselate/README.md

@@ -4,36 +4,34 @@
 
 ## tesselate
 
-Tesselates a [Feature\<Polygon>][1] into a [FeatureCollection\<Polygon>][2] of triangles
-using [earcut][3].
+Tesselates a polygon or multipolygon into a collection of triangle polygons
+using [earcut][1].
 
 ### Parameters
 
-*   `poly` **[Feature][4]<[Polygon][5]>** the polygon to tesselate
+*   `poly` **[Feature][2]<([Polygon][3] | [MultiPolygon][4])>** the polygon to tesselate
 
 ### Examples
 
 ```javascript
-var poly = turf.polygon([[[11, 0], [22, 4], [31, 0], [31, 11], [21, 15], [11, 11], [11, 0]]]);
-var triangles = turf.tesselate(poly);
+const poly = turf.polygon([[[11, 0], [22, 4], [31, 0], [31, 11], [21, 15], [11, 11], [11, 0]]]);
+const triangles = turf.tesselate(poly);
 
 //addToMap
-var addToMap = [poly, triangles]
+const addToMap = [poly, triangles]
 ```
 
-Returns **[FeatureCollection][6]<[Polygon][5]>** a geometrycollection feature
+Returns **[FeatureCollection][5]<[Polygon][3]>** collection of polygon tesselations
 
-[1]: Feature<Polygon>
+[1]: https://github.com/mapbox/earcut
 
-[2]: FeatureCollection<Polygon>
+[2]: https://tools.ietf.org/html/rfc7946#section-3.2
 
-[3]: https://github.com/mapbox/earcut
+[3]: https://tools.ietf.org/html/rfc7946#section-3.1.6
 
-[4]: https://tools.ietf.org/html/rfc7946#section-3.2
+[4]: https://tools.ietf.org/html/rfc7946#section-3.1.7
 
-[5]: https://tools.ietf.org/html/rfc7946#section-3.1.6
-
-[6]: https://tools.ietf.org/html/rfc7946#section-3.3
+[5]: 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-tesselate/bench.ts

@@ -1,4 +1,4 @@
-import Benchmark from "benchmark";
+import Benchmark, { Event } from "benchmark";
 import { polygon } from "@turf/helpers";
 import { tesselate } from "./index.js";
 
@@ -20,5 +20,5 @@ var poly = polygon([
  */
 new Benchmark.Suite("turf-tesselate")
   .add("polygon", () => tesselate(poly))
-  .on("cycle", (e) => console.log(String(e.target)))
+  .on("cycle", (e: Event) => console.log(String(e.target)))
   .run();

packages/turf-tesselate/earcut.d.ts

@@ -0,0 +1,9 @@
+declare module "earcut" {
+  declare function earcut(
+    vertices: number[],
+    holes: number[],
+    dimensions: number
+  );
+
+  export default earcut;
+}

packages/turf-tesselate/index.ts

@@ -0,0 +1,96 @@
+import {
+  Feature,
+  FeatureCollection,
+  MultiPolygon,
+  Polygon,
+  Position,
+} from "geojson";
+import earcut from "earcut";
+import { polygon } from "@turf/helpers";
+
+/**
+ * Tesselates a polygon or multipolygon into a collection of triangle polygons
+ * using [earcut](https://github.com/mapbox/earcut).
+ *
+ * @name tesselate
+ * @param {Feature<Polygon|MultiPolygon>} poly the polygon to tesselate
+ * @returns {FeatureCollection<Polygon>} collection of polygon tesselations
+ * @example
+ * const poly = turf.polygon([[[11, 0], [22, 4], [31, 0], [31, 11], [21, 15], [11, 11], [11, 0]]]);
+ * const triangles = turf.tesselate(poly);
+ *
+ * //addToMap
+ * const addToMap = [poly, triangles]
+ */
+function tesselate(
+  poly: Feature<Polygon | MultiPolygon>
+): FeatureCollection<Polygon> {
+  if (
+    !poly.geometry ||
+    (poly.geometry.type !== "Polygon" && poly.geometry.type !== "MultiPolygon")
+  ) {
+    throw new Error("input must be a Polygon or MultiPolygon");
+  }
+
+  const fc: FeatureCollection<Polygon> = {
+    type: "FeatureCollection",
+    features: [],
+  };
+
+  if (poly.geometry.type === "Polygon") {
+    fc.features = processPolygon(poly.geometry.coordinates);
+  } else {
+    poly.geometry.coordinates.forEach(function (coordinates) {
+      fc.features = fc.features.concat(processPolygon(coordinates));
+    });
+  }
+
+  return fc;
+}
+
+function processPolygon(coordinates: Position[][]) {
+  const data = flattenCoords(coordinates);
+  const dim = 2;
+  const result = earcut(data.vertices, data.holes, dim);
+
+  const features: Feature<Polygon>[] = [];
+  const vertices: Position[] = [];
+
+  result.forEach(function (vert: any, i: number) {
+    const index = result[i];
+    vertices.push([data.vertices[index * dim], data.vertices[index * dim + 1]]);
+  });
+
+  for (var i = 0; i < vertices.length; i += 3) {
+    const coords = vertices.slice(i, i + 3);
+    coords.push(vertices[i]);
+    features.push(polygon([coords]));
+  }
+
+  return features;
+}
+
+function flattenCoords(data: Position[][]) {
+  const dim: number = data[0][0].length,
+    result: { vertices: number[]; holes: number[]; dimensions: number } = {
+      vertices: [],
+      holes: [],
+      dimensions: dim,
+    };
+  let holeIndex = 0;
+
+  for (let i = 0; i < data.length; i++) {
+    for (let j = 0; j < data[i].length; j++) {
+      for (let d = 0; d < dim; d++) result.vertices.push(data[i][j][d]);
+    }
+    if (i > 0) {
+      holeIndex += data[i - 1].length;
+      result.holes.push(holeIndex);
+    }
+  }
+
+  return result;
+}
+
+export { tesselate };
+export default tesselate;

packages/turf-tesselate/package.json

@@ -60,14 +60,18 @@
   },
   "devDependencies": {
     "@types/benchmark": "^2.1.5",
+    "@types/tape": "^4.2.32",
     "benchmark": "^2.1.4",
     "npm-run-all": "^4.1.5",
     "tape": "^5.7.2",
     "tsup": "^8.0.1",
-    "tsx": "^4.6.2"
+    "tsx": "^4.6.2",
+    "typescript": "^5.2.2"
   },
   "dependencies": {
     "@turf/helpers": "workspace:^",
-    "earcut": "^2.2.4"
+    "@types/geojson": "7946.0.8",
+    "earcut": "^2.2.4",
+    "tslib": "^2.6.2"
   }
 }