From 934e4378d83881fb1fedfa0b201b7bf0b645b747 Mon Sep 17 00:00:00 2001
From: David Greenspan <dgreenspan@alum.mit.edu>
Date: Mon, 8 Jul 2013 21:03:18 -0700
Subject: [PATCH] detach, don't destroy, certain children in rebuild

---
 examples/unfinished/shark/client/shark.js |  6 ++++-
 packages/ui/dom.js                        | 27 ++++++++++++++++-------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/examples/unfinished/shark/client/shark.js b/examples/unfinished/shark/client/shark.js
index 36e038cf87..0579a964f7 100644
--- a/examples/unfinished/shark/client/shark.js
+++ b/examples/unfinished/shark/client/shark.js
@@ -95,6 +95,10 @@ Either = UIComponent.extend({
 Meteor.startup(function () {
   Session.set('which', 'Span');
 
-  var x = Either.create({isRoot: true});
+  // leak `x` for fooling around in the console
+  x = Either.create({isRoot: true});
   x.attach(document.body);
+
+  // leak `c`
+  (c = _UI.Counter.create({isRoot:true})).attach(document.body);
 });
diff --git a/packages/ui/dom.js b/packages/ui/dom.js
index 6a9ca4c8ba..6e04c62445 100644
--- a/packages/ui/dom.js
+++ b/packages/ui/dom.js
@@ -207,10 +207,11 @@ Component({
     // Should work whether this component is detached or attached!
     // In other words, it may reside in an offscreen element.
 
-    var A = self.firstNode();
-    var B = self.lastNode();
-    var parentNode = B.parentNode;
-    var nextNode = B.nextSibling || null;
+    var firstNode = self.firstNode();
+    var lastNode = self.lastNode();
+    var parentNode = lastNode.parentNode;
+    var nextNode = lastNode.nextSibling || null;
+    var prevNode = firstNode.previousSibling || null;
 
     // for efficiency, do a quick check to see if we've *ever*
     // had children or if we are still using the prototype's
@@ -222,19 +223,29 @@ Component({
         var children = self.children;
         for (var k in children) {
           var child = children[k];
-          if (child.isAttached || builtChildren[k]) {
-            // destroy first, then remove (which doesn't affect DOM)
+          if (builtChildren[k]) {
+            // destroy first, then remove
+            // (which doesn't affect DOM, which we will
+            // remove all at once)
             child.destroy();
             self.remove(child);
+          } else if (child.isAttached) {
+            // detach the child; we don't have a good way
+            // of keeping this from affecting the DOM
+            child.detach();
           }
         }
       });
     }
 
     var oldNodes = [];
-    for (var n = A; n !== B; n = n.nextSibling)
+    // must be careful as call to `detach` above may have
+    // must with firstNode or lastNode
+    for (var n = prevNode ? prevNode.nextSibling :
+               parentNode.firstChild;
+         n && n !== nextNode;
+         n = n.nextSibling)
       oldNodes.push(n);
-    oldNodes.push(B);
 
     $(oldNodes).remove();