add unsorted option

src/controller.js

@@ -83,7 +83,7 @@ export default class TreemapController extends DatasetController {
 
     const w = xScale.right - xScale.left;
     const h = yScale.bottom - yScale.top;
-    const rect = {x: 0, y: 0, w, h, rtl: !!this.options.rtl};
+    const rect = {x: 0, y: 0, w, h, rtl: !!this.options.rtl, unsorted: !!this.options.unsorted};
 
     if (rectNotEqual(this._rect, rect)) {
       this._rect = rect;

src/element.js

@@ -391,6 +391,7 @@ TreemapElement.defaults = {
     padding: 3
   },
   rtl: false,
+  unsorted: false,
   spacing: 0.5
 };
 

src/helpers/index.js

@@ -19,7 +19,8 @@ export function rectNotEqual(r1, r2) {
 		|| r1.y !== r2.y
 		|| r1.w !== r2.w
 		|| r1.h !== r2.h
-    || r1.rtl !== r2.rtl;
+    || r1.rtl !== r2.rtl
+    || r1.unsorted !== r2.unsorted;
 }
 
 export function arrayNotEqual(a, b) {

src/rect.js

@@ -35,6 +35,7 @@ export default class Rect {
   constructor(r) {
     r = r || {w: 1, h: 1};
     this.rtl = !!r.rtl;
+    this.unsorted = !!r.unsorted;
     this.x = r.x || r.left || 0;
     this.y = r.y || r.top || 0;
     this._ix = 0;

src/squarify.js

@@ -40,7 +40,10 @@ export default function squarify(values, rectangle, keys = [], grp, lvl, gsum) {
 
   const tmp = values.slice();
   let key = index(tmp, keys[0]);
-  sort(tmp, key);
+
+  if (!rectangle.unsorted) {
+    sort(tmp, key);
+  }
 
   const val = (idx) => key ? +tmp[idx][key] : +tmp[idx];
   const gval = (idx) => grp && tmp[idx][grp];