diff --git a/README.md b/README.md
index 334c9e6..fd99aae 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ A [quadtree](https://en.wikipedia.org/wiki/Quadtree) recursively partitions two-
 
 ## Installing
 
-If you use NPM, `npm install d3-quadtree`. Otherwise, download the [latest release](https://github.com/d3/d3-quadtree/releases/latest). You can also load directly from [d3js.org](https://d3js.org), either as a [standalone library](https://d3js.org/d3-quadtree.v1.min.js) or as part of [D3](https://github.com/d3/d3). AMD, CommonJS, and vanilla environments are supported. In vanilla, a `d3` global is exported:
+If you use NPM, `npm install d3-quadtree`. Otherwise, download the [latest release](https://github.com/d3/d3-quadtree/releases/latest). You can also load directly from [d3js.org](https://d3js.org), either as a [standalone library](https://d3js.org/d3-quadtree.v2.min.js) or as part of [D3](https://github.com/d3/d3). AMD, CommonJS, and vanilla environments are supported. In vanilla, a `d3` global is exported:
 
 ```html
 <script src="https://d3js.org/d3-quadtree.v1.min.js"></script>
diff --git a/package.json b/package.json
index 3fd9691..f1616f5 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,9 @@
 {
   "name": "d3-quadtree",
-  "version": "1.0.7",
+  "version": "2.0.0-rc.1",
+  "publishConfig": {
+    "tag": "next"
+  },
   "description": "Two-dimensional recursive spatial subdivision.",
   "keywords": [
     "d3",
diff --git a/src/add.js b/src/add.js
index ac7c4d1..985adfc 100644
--- a/src/add.js
+++ b/src/add.js
@@ -1,5 +1,5 @@
 export default function(d) {
-  var x = +this._x.call(null, d),
+  const x = +this._x.call(null, d),
       y = +this._y.call(null, d);
   return add(this.cover(x, y), x, y, d);
 }
diff --git a/src/cover.js b/src/cover.js
index a981a3d..e1d47cd 100644
--- a/src/cover.js
+++ b/src/cover.js
@@ -16,7 +16,7 @@ export default function(x, y) {
 
   // Otherwise, double repeatedly to cover.
   else {
-    var z = x1 - x0,
+    var z = x1 - x0 || 1,
         node = this._root,
         parent,
         i;
diff --git a/test/cover-test.js b/test/cover-test.js
index cd49d09..08c42a0 100644
--- a/test/cover-test.js
+++ b/test/cover-test.js
@@ -77,3 +77,8 @@ tape("quadtree.cover(x, y) does not wrap the root node if it is undefined", func
   test.equal(q.copy().cover(-3, -3).root(), undefined);
   test.end();
 });
+
+tape("quadtree.cover() does not crash on huge values", function(test) {
+  d3_quadtree.quadtree([[1e23, 0]]);
+  test.end();
+});