Create new @visx/delaunay package

jest.config.js

@@ -44,6 +44,6 @@ module.exports = {
   verbose: false,
   testPathIgnorePatterns: ['<rootDir>/packages/visx-demo'],
   transformIgnorePatterns: [
-    'node_modules/(?!(d3-(array|color|format|interpolate|scale|time|time-format)|internmap)/)',
+    'node_modules/(?!(d3-(array|color|format|interpolate|scale|time|time-format)|delaunator|internmap|robust-predicates)/)',
   ],
 };

packages/visx-delaunay/.npmrc

@@ -0,0 +1 @@
+package-lock=false

packages/visx-delaunay/Readme.md

@@ -0,0 +1,67 @@
+# @visx/delaunay
+
+<a title="@visx/delaunay npm downloads" href="https://www.npmjs.com/package/@visx/delaunay">
+  <img src="https://img.shields.io/npm/dm/@visx/delaunay.svg?style=flat-square" />
+</a>
+
+## Overview
+
+A Voronoi diagram partitions a two-dimensional plane into regions based on a set of input points.
+Each unique input point maps to a corresponding region, where each region represents _all points
+that are closer to the input point than to any other input point_.
+
+Not only are Voronoi diagrams 😍, but they can be used to
+[improve the interactive experience of a visualization](https://www.visualcinnamon.com/2015/07/voronoi.html).
+This is most often accomplished by overlaying an invisible voronoi grid on top of the visualization
+to increase the target area of interaction sites such as points on a scatter plot.
+
+The `@visx/delaunay` package provides a wrapper around the existing
+[d3-delaunay](https://github.com/d3/d3-delaunay) package with some `react`-specific utilities.
+
+## Installation
+
+```
+npm install --save @visx/delaunay
+```
+
+## Usage
+
+The `@visx/delaunay` package exports a wrapped version of the d3 `voronoi` and `delaunay` layouts for flexible usage,
+as well as a `<Polygon />` component for rendering Voronoi and Delaunay regions.
+
+```js
+import { voronoi, Polygon } from '@visx/delaunay';
+
+const points = Array(n).fill(null).map(() => ({
+  x: Math.random() * innerWidth,
+  y: Math.random() * innerHeight,
+}));
+
+// width + height set an extent on the voronoi
+// x + y set relevant accessors depending on the shape of your data
+const voronoiDiagram = voronoi({
+  data: points,
+  x: d => d.x,
+  y: d => d.y,
+  width,
+  height,
+});
+
+const polygons = Array.from(voronoiDiagram.cellPolygons());
+
+return (
+  <svg>
+    <Group>
+      {polygons.map((polygon) => (
+        <Polygon key={...} polygon={polygon} />
+      ))}
+      {points.map(({ x, y }) => (
+        <circle key={...} cx={x} cy={y} />
+      )}
+    </Group>
+  </svg>
+)
+```
+
+Additional information about the voronoi diagram API can be found in the
+[d3-delaunay documentation](https://github.com/d3/d3-delaunay#voronoi).

packages/visx-delaunay/package.json

@@ -0,0 +1,42 @@
+{
+  "name": "@visx/delaunay",
+  "version": "1.0.0",
+  "description": "visx delaunay",
+  "sideEffects": false,
+  "main": "lib/index.js",
+  "module": "esm/index.js",
+  "types": "lib/index.d.ts",
+  "files": [
+    "lib",
+    "esm"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/airbnb/visx.git"
+  },
+  "keywords": [
+    "visx",
+    "react",
+    "d3",
+    "visualizations",
+    "charts"
+  ],
+  "author": "@SheaJanke",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/airbnb/visx/issues"
+  },
+  "homepage": "https://github.com/airbnb/visx#readme",
+  "publishConfig": {
+    "access": "public"
+  },
+  "dependencies": {
+    "@types/react": "*",
+    "@visx/vendor": "3.2.0",
+    "classnames": "^2.3.1",
+    "prop-types": "^15.6.1"
+  },
+  "peerDependencies": {
+    "react": "^16.3.0-0 || ^17.0.0-0 || ^18.0.0-0"
+  }
+}

packages/visx-delaunay/src/components/Polygon.tsx

@@ -0,0 +1,24 @@
+import React from 'react';
+import cx from 'classnames';
+
+export type PolygonProps = {
+  /** Override render function which is provided polygon and generated path. */
+  children?: ({ path, polygon }: { path: string; polygon: [number, number][] }) => React.ReactNode;
+  /** className to apply to path element. */
+  className?: string;
+  /** Array of coordinate arrays for the polygon (e.g., [[x,y], [x1,y1], ...]), used to generate polygon path. */
+  polygon?: [number, number][];
+};
+
+export default function Polygon({
+  polygon,
+  className,
+  children,
+  ...restProps
+}: PolygonProps & Omit<React.SVGProps<SVGPathElement>, keyof PolygonProps>) {
+  if (!polygon) return null;
+  const path = `M${polygon.join('L')}Z`;
+  if (children) return <>{children({ path, polygon })}</>;
+
+  return <path className={cx('visx-delaunay-polygon', className)} d={path} {...restProps} />;
+}

packages/visx-delaunay/src/delaunay.ts

@@ -0,0 +1,17 @@
+import { Delaunay } from '@visx/vendor/d3-delaunay';
+
+interface Config<Datum> {
+  /** The data for the delaunay triangulation */
+  data?: Datum[];
+  /** Set the x-value accessor function for the delaunay triangulation. */
+  x: (d: Datum) => number;
+  /** Set the y-value accessor function for the delaunay triangulation. */
+  y: (d: Datum) => number;
+}
+
+/**
+ * Returns a configured d3 delaunay triangulation. See d3-delaunay for the complete API reference.
+ */
+export default function delaunay<Datum>({ data = [], x, y }: Config<Datum>) {
+  return Delaunay.from(data, x, y);
+}

packages/visx-delaunay/src/index.ts

@@ -0,0 +1,3 @@
+export { default as delaunay } from './delaunay';
+export { default as voronoi } from './voronoi';
+export { default as Polygon } from './components/Polygon';

packages/visx-delaunay/src/voronoi.ts

@@ -0,0 +1,30 @@
+import { Delaunay } from '@visx/vendor/d3-delaunay';
+
+const CLIP_PADDING = 1;
+
+interface Config<Datum> {
+  /** The data for the voronoi diagram */
+  data?: Datum[];
+  /** The total width of the voronoi diagram. */
+  width?: number;
+  /** The total width of the voronoi diagram. */
+  height?: number;
+  /** Set the x-value accessor function for the voronoi diagram. */
+  x: (d: Datum) => number;
+  /** Set the y-value accessor function for the voronoi diagram. */
+  y: (d: Datum) => number;
+}
+
+/**
+ * Returns a configured d3 voronoi diagram for the given data. See d3-delaunay
+ * for the complete API reference.
+ */
+export default function voronoi<Datum>({ data = [], width = 0, height = 0, x, y }: Config<Datum>) {
+  const delaunay = Delaunay.from(data, x, y);
+  return delaunay.voronoi([
+    -CLIP_PADDING,
+    -CLIP_PADDING,
+    width + CLIP_PADDING,
+    height + CLIP_PADDING,
+  ]);
+}

packages/visx-delaunay/test/Polygon.test.tsx

@@ -0,0 +1,35 @@
+import React from 'react';
+import { shallow } from 'enzyme';
+
+import { Polygon } from '../src';
+
+describe('<Polygon />', () => {
+  const polygon: [number, number][] = new Array(3).fill(null).map((_, i) => [i, i]);
+
+  const props = { polygon };
+
+  test('it should be defined', () => {
+    expect(Polygon).toBeDefined();
+  });
+
+  test('it should not render without a polygon', () => {
+    const wrapper = shallow(<Polygon />);
+    expect(wrapper.type()).toBeNull();
+  });
+
+  test('it should render a path', () => {
+    const wrapper = shallow(<Polygon {...props} />);
+    expect(wrapper.find('path')).toHaveLength(1);
+  });
+
+  test('it should set a d attribute based on the polygon prop', () => {
+    const wrapper = shallow(<Polygon {...props} />);
+    const d = 'M0,0L1,1L2,2Z';
+    expect(wrapper.find('path').props().d).toEqual(d);
+  });
+
+  test('it should add extra (non-func) props to the path element', () => {
+    const wrapper = shallow(<Polygon {...props} fill="orange" />);
+    expect(wrapper.find('path').props().fill).toBe('orange');
+  });
+});

packages/visx-delaunay/test/delaunay.test.ts

@@ -0,0 +1,26 @@
+import { delaunay } from '../src';
+
+const data = [
+  { x: 10, y: 10 },
+  { x: 10, y: 20 },
+  { x: 20, y: 20 },
+  { x: 20, y: 10 },
+];
+
+describe('delaunay', () => {
+  test('it should be defined', () => {
+    expect(delaunay).toBeDefined();
+  });
+
+  test('it should find closest point', () => {
+    const delaunayDiagram = delaunay({ data, x: (d) => d.x, y: (d) => d.y });
+    expect(delaunayDiagram.find(9, 11)).toBe(0);
+    expect(delaunayDiagram.find(11, 19)).toBe(1);
+    expect(delaunayDiagram.find(21, 19)).toBe(2);
+  });
+
+  test('the delaunay triagulation of a square should contain two triangles', () => {
+    const delaunayDiagram = delaunay({ data, x: (d) => d.x, y: (d) => d.y });
+    expect(Array.from(delaunayDiagram.trianglePolygons())).toHaveLength(2);
+  });
+});

packages/visx-delaunay/test/tsconfig.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "composite": false,
+    "emitDeclarationOnly": false,
+    "noEmit": true,
+    "rootDir": "."
+  },
+  "extends": "../../../tsconfig.options.json",
+  "include": ["**/*", "../types/**/*", "../../../types/**/*"],
+  "references": [
+    {
+      "path": ".."
+    }
+  ]
+}

packages/visx-delaunay/test/voronoi.test.ts

@@ -0,0 +1,29 @@
+import { voronoi } from '../src';
+
+const x = () => 123;
+const y = () => 123;
+
+describe('voronoi', () => {
+  test('it should be defined', () => {
+    expect(voronoi).toBeDefined();
+  });
+
+  test('width and height params should define extent', () => {
+    const width = 17;
+    const height = 99;
+    const v = voronoi({ width, height, x, y });
+    expect(v.xmin).toBe(-1);
+    expect(v.ymin).toBe(-1);
+    expect(v.xmax).toEqual(width + 1);
+    expect(v.ymax).toEqual(height + 1);
+  });
+
+  test('100 random points should give 100 cell polygons', () => {
+    const data = new Array(100).fill(null).map(() => ({
+      x: Math.random(),
+      y: Math.random(),
+    }));
+    const v = voronoi({ data, x: (d) => d.x, y: (d) => d.y });
+    expect(Array.from(v.cellPolygons())).toHaveLength(100);
+  });
+});

packages/visx-delaunay/tsconfig.json

@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "declarationDir": "lib",
+    "outDir": "lib",
+    "rootDir": "src"
+  },
+  "exclude": [
+    "lib",
+    "test"
+  ],
+  "extends": "../../tsconfig.options.json",
+  "include": [
+    "src/**/*",
+    "types/**/*",
+    "../../types/**/*"
+  ],
+  "references": [
+    {
+      "path": "../visx-vendor"
+    }
+  ]
+}

packages/visx-demo/package.json

@@ -40,6 +40,7 @@
     "@visx/chord": "3.0.0",
     "@visx/clip-path": "3.0.0",
     "@visx/curve": "3.0.0",
+    "@visx/delaunay": "1.0.0",
     "@visx/drag": "3.0.1",
     "@visx/event": "3.0.1",
     "@visx/geo": "3.0.0",