From 7ee062fa2ab88a735552c2761ff7c5901a842178 Mon Sep 17 00:00:00 2001
From: guybedford <guybedford@gmail.com>
Date: Tue, 18 Nov 2014 14:54:51 +0200
Subject: [PATCH] dedupe overridden jspm properties

---
 lib/config/package.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/config/package.js b/lib/config/package.js
index 66f7fb837..cc20e11e1 100644
--- a/lib/config/package.js
+++ b/lib/config/package.js
@@ -131,8 +131,6 @@ PackageJSON.prototype.read = function() {
 
 PackageJSON.prototype.write = function() {
   var pjson = this.jspmPrefix ? {} : this.originalPjson;
-  if (this.jspmPrefix)
-    this.originalPjson.jspm = pjson;
 
   var defaults = this.defaults;
 
@@ -196,6 +194,15 @@ PackageJSON.prototype.write = function() {
   if (!hasProperties(pjson.buildConfig))
     delete pjson.buildConfig;
 
+  // dedupe jspm properties against base properties
+  if (this.jspmPrefix) {
+    for (var p in pjson) {
+      if (this.originalPjson[p] === pjson[p])
+        delete pjson[p];
+    }
+    this.originalPjson.jspm = pjson;
+  }
+
   // NB check that the file hasn't changed since we opened it and if so, prompt
   return asp(fs.writeFile)(this.fileName, JSON.stringify(this.originalPjson, null, 2) + '\n');
 }