d3.geom.voronoi: return the configured size.

d3.js

@@ -4150,8 +4150,8 @@ d3 = function() {
       if (_ == null) {
         clip = null;
       } else {
-        var w = +_[0], h = +_[1];
-        clip = d3.geom.polygon([ [ 0, 0 ], [ 0, h ], [ w, h ], [ w, 0 ] ]).clip;
+        size = [ +_[0], +_[1] ];
+        clip = d3.geom.polygon([ [ 0, 0 ], [ 0, size[1] ], size, [ size[0], 0 ] ]).clip;
       }
       return voronoi;
     };
@@ -4483,6 +4483,8 @@ d3 = function() {
           });
         }
       } else {
+        x1 = y1 = Infinity;
+        x2 = y2 = -Infinity;
         while (++i < n) {
           points.push(d = {
             x: +fx.call(this, d = data[i], i),
@@ -4543,9 +4545,12 @@ d3 = function() {
       if (!arguments.length) return x1 == null ? null : [ [ x1, y1 ], [ x2, y2 ] ];
       if (_ == null) {
         x1 = y1 = x2 = y2 = null;
-      } else {
+      } else if (Array.isArray(_[0])) {
         x1 = +_[0][0], y1 = +_[0][1];
         x2 = +_[1][0], y2 = +_[1][1];
+      } else {
+        x1 = y1 = 0;
+        x2 = +_[0], y2 = +_[1];
       }
       return quadtree;
     };

src/geom/voronoi.js

@@ -143,8 +143,8 @@ d3.geom.voronoi = function(vertices) {
     if (_ == null) {
       clip = null;
     } else {
-      var w = +_[0], h = +_[1];
-      clip = d3.geom.polygon([[0, 0], [0, h], [w, h], [w, 0]]).clip;
+      size = [+_[0], +_[1]];
+      clip = d3.geom.polygon([[0, 0], [0, size[1]], size, [size[0], 0]]).clip;
     }
     return voronoi;
   };

test/geom/voronoi-test.js

@@ -15,6 +15,13 @@ suite.addBatch({
       "has no defined size": function(v) {
         assert.isNull(v.size());
       },
+      "returns the configured size": function(v) {
+        try {
+          assert.deepEqual(v.size([100, 100]).size(), [100, 100]);
+        } finally {
+          v.size(null);
+        }
+      },
       "has the default x-accessor, d[0]": function(v) {
         assert.strictEqual(v.x()([42, 43]), 42);
       },