fix(ngRepeat): correctly apply $last if repeating over object

If the $last property is calculated from the original collectionLength
on an object and properties starting with $ were filtered out, then $last
is never applied and $middle is applied erroniously.

Closes angular#1789

Author: petebacondarwin

src/ng/directive/ngRepeat.js

@@ -92,14 +92,17 @@ var ngRepeatDirective = ngDirective({
       scope.$watch(function ngRepeatWatch(scope){
         var index, length,
             collection = scope.$eval(rhs),
-            collectionLength = size(collection, true),
-            childScope,
+            cursor = iterStartElement,     // current position of the node
             // Same as lastOrder but it has the current state. It will become the
             // lastOrder on the next iteration.
             nextOrder = new HashQueueMap(),
+            arrayLength,
+            childScope,
             key, value, // key/value of iteration
-            array, last,       // last object information {scope, element, index}
-            cursor = iterStartElement;     // current position of the node
+            array,
+            last;       // last object information {scope, element, index}
+
+
 
         if (!isArray(collection)) {
           // if object, extract keys, sort them and use to determine order of iteration over obj props
@@ -114,6 +117,8 @@ var ngRepeatDirective = ngDirective({
           array = collection || [];
         }
 
+        arrayLength = array.length;
+
         // we are not using forEach for perf reasons (trying to avoid #call)
         for (index = 0, length = array.length; index < length; index++) {
           key = (collection === array) ? index : array[index];
@@ -149,7 +154,7 @@ var ngRepeatDirective = ngDirective({
           childScope.$index = index;
 
           childScope.$first = (index === 0);
-          childScope.$last = (index === (collectionLength - 1));
+          childScope.$last = (index === (arrayLength - 1));
           childScope.$middle = !(childScope.$first || childScope.$last);
 
           if (!last) {

test/ng/directive/ngRepeatSpec.js

@@ -293,6 +293,21 @@ describe('ngRepeat', function() {
   });
 
 
+  it('should calculate $first, $middle and $last when we filter out properties from an obj', function() {
+    element = $compile(
+        '<ul>' +
+            '<li ng-repeat="(key, val) in items">{{key}}:{{val}}:{{$first}}-{{$middle}}-{{$last}}|</li>' +
+            '</ul>')(scope);
+    scope.items = {'misko':'m', 'shyam':'s', 'doug':'d', 'frodo':'f', '$toBeFilteredOut': 'xxxx'};
+    scope.$digest();
+    expect(element.text()).
+        toEqual('doug:d:true-false-false|' +
+        'frodo:f:false-true-false|' +
+        'misko:m:false-true-false|' +
+        'shyam:s:false-false-true|');
+  });
+
+
   it('should ignore $ and $$ properties', function() {
     element = $compile('<ul><li ng-repeat="i in items">{{i}}|</li></ul>')(scope);
     scope.items = ['a', 'b', 'c'];