From 6cf4e3fe9b5eacf446b16e47c9a689a08ff95a0e Mon Sep 17 00:00:00 2001
From: Jeff Avallone <jeff.avallone@gmail.com>
Date: Thu, 16 Apr 2015 17:10:30 -0400
Subject: [PATCH] Tweaking normalizeBBox

Using defaults instead of extend seems to more clearly illustrate the
intent.
---
 src/js/util.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/js/util.js b/src/js/util.js
index aebaf14..c0e22cd 100644
--- a/src/js/util.js
+++ b/src/js/util.js
@@ -22,11 +22,11 @@ function customEvent(name, detail) {
 // - __box__ - Bounding box object to update. Attributes `ax`, `ax2`, and `ay`
 //    will be added if they are not already defined.
 function normalizeBBox(box) {
-  return _.extend({
+  return _.defaults(box, {
     ax: box.x,
     ax2: box.x2,
     ay: box.cy
-  }, box);
+  });
 }
 
 // Positions a collection of items with their axis points aligned along a