Add d3-quadtree.

README.md

@@ -23,6 +23,7 @@ If you use NPM, `npm install d3@4.0.0-alpha.4`. Otherwise, download the [latest
 * [Number Formats](#number-formats)
 * [Paths](#paths)
 * [Polygons](#polygons)
+* [Quadtrees](#quadtrees)
 * [Random Numbers](#random-numbers)
 * [Requests](#requests)
 * [Scales](#scales) ([Continuous](#continuous), [Sequential](#sequential), [Quantize](#quantize), [Ordinal](#ordinal), [Categorical](#categorical))
@@ -326,6 +327,12 @@ Geometric operations for two-dimensional polygons.
 * [d3.polygonContains](https://github.com/d3/d3-polygon#polygonContains) - test whether a point is inside a polygon.
 * [d3.polygonLength](https://github.com/d3/d3-polygon#polygonLength) - compute the length of the given polygon’s perimeter.
 
+## [Quadtrees](https://github.com/d3/d3-quadtree)
+
+Two-dimensional recursive spatial subdivision.
+
+* [d3.quadtree](https://github.com/d3/d3-quadtree#quadtree) - create a new quadtree generator.
+
 ## [Random Numbers](https://github.com/d3/d3-random)
 
 Generate random numbers from various distributions.

index.js

@@ -95,6 +95,10 @@ export {
   path
 } from "d3-path";
 
+export {
+  quadtree
+} from "d3-quadtree";
+
 export {
   arc,
   area,

package.json

@@ -46,6 +46,7 @@
     "d3-interpolate": "0.4.0",
     "d3-path": "0.1.3",
     "d3-polygon": "0.2.0",
+    "d3-quadtree": "0.1.1",
     "d3-random": "0.2.0",
     "d3-request": "0.3.0",
     "d3-scale": "0.5.0",