trigger layoutComplete even if no items

Fixes #28

bower.json

@@ -1,6 +1,6 @@
 {
   "name": "packery",
-  "version": "1.0.2",
+  "version": "1.0.3",
   "author": "David DeSandro / Metafizzy",
   "main": [
     "./js/rect.js",

js/packery.js

@@ -1,5 +1,5 @@
 /*!
- * Packery v1.0.2
+ * Packery v1.0.3
  * bin-packing layout library
  * http://packery.metafizzy.co
  *
@@ -333,15 +333,20 @@ Packery.prototype.layoutItems = function( items, isInstant ) {
   // console.log('layout Items');
   var layoutItems = this._getLayoutItems( items );
 
-  this._itemsOn( layoutItems, 'layout', function onItemsLayout() {
-    this.emitEvent( 'layoutComplete', [ this, layoutItems ] );
-  });
-
-  for ( var i=0, len = layoutItems.length; i < len; i++ ) {
-    var item = layoutItems[i];
-    // listen to layout events for callback
-    this._packItem( item );
-    this._layoutItem( item, isInstant );
+  if ( !layoutItems || !layoutItems.length ) {
+    // no items, just emit layout complete with empty array
+    this.emitEvent( 'layoutComplete', [ this, [] ] );
+  } else {
+    this._itemsOn( layoutItems, 'layout', function onItemsLayout() {
+      this.emitEvent( 'layoutComplete', [ this, layoutItems ] );
+    });
+
+    for ( var i=0, len = layoutItems.length; i < len; i++ ) {
+      var item = layoutItems[i];
+      // listen to layout events for callback
+      this._packItem( item );
+      this._layoutItem( item, isInstant );
+    }
   }
 
   // set container size

test/defaults-empty.js

@@ -10,6 +10,15 @@ test( 'defaults / empty', function() {
   equal( pckry.stampedElements.length, 0, 'zero stamped elements' );
   equal( Packery.data( empty ), pckry, 'data method returns instance' );
   ok( pckry.isResizeBound, 'isResizeBound' );
+
+  pckry.on( 'layoutComplete', function( obj, items ) {
+    ok( true, 'layoutComplete triggered with no items' );
+    equal( items.length, 0, 'no items' );
+    start();
+    return true; // bind once
+  });
+  stop();
+  pckry.layout();
 });
 
 })();