From fe173180125f810ba3a95c062b039ce6f1a939a5 Mon Sep 17 00:00:00 2001
From: Xaser Acheron <xaser.88@gmail.com>
Date: Wed, 13 Apr 2016 09:53:54 -0500
Subject: [PATCH] fixed tweenPie causing error when interpolating object-valued
 crossfilter groups

---
 src/pie-chart.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/pie-chart.js b/src/pie-chart.js
index 145191695..e6c5bf527 100644
--- a/src/pie-chart.js
+++ b/src/pie-chart.js
@@ -431,6 +431,9 @@ dc.pieChart = function (parent, chartGroup) {
         var current = this._current;
         if (isOffCanvas(current)) {
             current = {startAngle: 0, endAngle: 0};
+        } else {
+            // only interpolate startAngle & endAngle, not the whole data object
+            current = {startAngle: current.startAngle, endAngle: current.endAngle};
         }
         var i = d3.interpolate(current, b);
         this._current = i(0);