Slightly cleaner.

src/treemap/binary.js

@@ -1,44 +1,44 @@
 export default function(parent, x0, y0, x1, y1) {
-  var nodes = parent.children;
-  var sums = [0];
-  for (var i = 0; i < nodes.length; i++) {
-    sums[i+1] = sums[i] + nodes[i].value;
+  var nodes = parent.children,
+      i, n = nodes.length,
+      sum, sums = new Array(n + 1);
+
+  for (sums[0] = sum = i = 0; i < n; ++i) {
+    sums[i + 1] = sum += nodes[i].value;
   }
-  partition(nodes, sums, 0, nodes.length, parent.value, x0, y0, x1, y1);
-}
 
+  partition(0, n, parent.value, x0, y0, x1, y1);
 
-function partition(nodes, sums, i, j, value, x0, y0, x1, y1) {
-  if (i >= j - 1) {
-    nodes = nodes[i];
-    nodes.x0 = x0, nodes.y0 = y0;
-    nodes.x1 = x1, nodes.y1 = y1;
-    return;
-  }
+  function partition(i, j, value, x0, y0, x1, y1) {
+    if (i >= j - 1) {
+      var node = nodes[i];
+      node.x0 = x0, node.y0 = y0;
+      node.x1 = x1, node.y1 = y1;
+      return;
+    }
 
-  var offset = sums[i];
-  var goal = (value / 2) + offset;
+    var valueOffset = sums[i],
+        valueTarget = (value / 2) + valueOffset,
+        k = i + 1,
+        hi = j - 1;
 
-  var k = i+1, ub = j-1, mid;
-  while(k < ub) {
-    mid = (k + ub) >>> 1;
-    if (sums[mid] < goal) {
-      k = mid+1;
-    } else {
-      ub = mid;
+    while (k < hi) {
+      var mid = k + hi >>> 1;
+      if (sums[mid] < valueTarget) k = mid + 1;
+      else hi = mid;
     }
-  }
 
-  var valueLeft = sums[k] - offset;
-  var valueRight = value - valueLeft;
+    var valueLeft = sums[k] - valueOffset,
+        valueRight = value - valueLeft;
 
-  if ((y1 - y0) > (x1 - x0)) {
-    var yk = (y0 * valueRight + y1 * valueLeft) / value;
-    partition(nodes, sums, i, k, valueLeft, x0, y0, x1, yk);
-    partition(nodes, sums, k, j, valueRight, x0, yk, x1, y1);
-  } else {
-    var xk = (x0 * valueRight + x1 * valueLeft) / value;
-    partition(nodes, sums, i, k, valueLeft, x0, y0, xk, y1);
-    partition(nodes, sums, k, j, valueRight, xk, y0, x1, y1);
+    if ((y1 - y0) > (x1 - x0)) {
+      var yk = (y0 * valueRight + y1 * valueLeft) / value;
+      partition(i, k, valueLeft, x0, y0, x1, yk);
+      partition(k, j, valueRight, x0, yk, x1, y1);
+    } else {
+      var xk = (x0 * valueRight + x1 * valueLeft) / value;
+      partition(i, k, valueLeft, x0, y0, xk, y1);
+      partition(k, j, valueRight, xk, y0, x1, y1);
+    }
   }
 }