From 44331d0ba6fff8eb43ac0100901efe6a2b77e24a Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Wed, 15 Jan 2014 04:00:25 -0700
Subject: [PATCH] Fix issues splitting panes with DOM events

* ::copyActiveItem guards against not having an active item
* The Pane constructor removes undefined items from params.items
---
 spec/pane-spec.coffee | 5 +++++
 src/pane.coffee       | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/spec/pane-spec.coffee b/spec/pane-spec.coffee
index 667c64cf8..7d2c802fa 100644
--- a/spec/pane-spec.coffee
+++ b/spec/pane-spec.coffee
@@ -23,6 +23,11 @@ describe "Pane", ->
       pane = new Pane(items: [new Item("A"), new Item("B")])
       expect(pane.activeItem).toBe pane.items[0]
 
+    it "compacts the items array", ->
+      pane = new Pane(items: [undefined, new Item("A"), null, new Item("B")])
+      expect(pane.items.length).toBe 2
+      expect(pane.activeItem).toBe pane.items[0]
+
   describe "::activateItem(item)", ->
     pane = null
 
diff --git a/src/pane.coffee b/src/pane.coffee
index 0f48fb0cd..e42d9f97d 100644
--- a/src/pane.coffee
+++ b/src/pane.coffee
@@ -31,7 +31,7 @@ class Pane extends Model
   constructor: (params) ->
     super
 
-    @items = Sequence.fromArray(params?.items ? [])
+    @items = Sequence.fromArray(compact(params?.items ? []))
     @activeItem ?= @items[0]
 
     @subscribe @items.onEach (item) =>
@@ -259,7 +259,8 @@ class Pane extends Model
 
   # Private:
   copyActiveItem: ->
-    @activeItem.copy?() ? atom.deserializers.deserialize(@activeItem.serialize())
+    if @activeItem?
+      @activeItem.copy?() ? atom.deserializers.deserialize(@activeItem.serialize())
 
   # Public: Creates a new pane to the left of the receiver.
   #