fix(orderBy): ensure correct ordering with arrays of objects and no predicate

Closes angular#11866

Author: petebacondarwin

src/ng/filter/orderBy.js

@@ -190,11 +190,11 @@ function orderByFilter($parse) {
     if (reverseOrder) { array.reverse(); }
     return array;
 
-    function getComparisonObject(value) {
+    function getComparisonObject(value, index) {
       return {
         value: value,
         predicateValues: predicates.map(function(predicate) {
-          return getPredicateValue(predicate.get(value));
+          return getPredicateValue(predicate.get(value), index);
         })
       };
     }
@@ -253,12 +253,19 @@ function orderByFilter($parse) {
     return '';
   }
 
-  function getPredicateValue(value) {
+  function getPredicateValue(value, index) {
     var type = typeof value;
     if (type === 'string') {
       value = value.toLowerCase();
     } else if (type === 'object') {
       value = objectToString(value);
+
+      // If the object is a POJO then it doesn't really have a well defined ordering
+      // To allow us to reverse the order of these objects, we artificially use its current
+      // index in the collection as its value
+      if (value === '[object Object]') {
+        value = index;
+      }
     }
     return { value: value, type: type };
   }

test/ng/filter/orderBySpec.js

@@ -143,6 +143,23 @@ describe('Filter: orderBy', function() {
     });
 
 
+    it('should reverse array of objects with predicate of "-"', function() {
+      var array = [
+        { id: 2 },
+        { id: 1 },
+        { id: 4 },
+        { id: 3 }
+      ];
+      var reversedArray = [
+        { id: 3 },
+        { id: 4 },
+        { id: 1 },
+        { id: 2 }
+      ];
+      expect(orderBy(array, '-')).toEqualData(reversedArray);
+    });
+
+
     it('should not reverse array of objects with null prototype and no predicate', function() {
       var array = [2,1,4,3].map(function(id) {
         var obj = Object.create(null);
@@ -161,10 +178,10 @@ describe('Filter: orderBy', function() {
         null
       ];
       expect(orderBy(array)).toEqualData([
-        { id: 2 },
-        { id: 3 },
         null,
-        null
+        null,
+        { id: 2 },
+        { id: 3 }
       ]);
     });
   });
@@ -304,10 +321,10 @@ describe('Filter: orderBy', function() {
       null
       ];
       expect(orderBy(array)).toEqualData([
-        { id: 2 },
-        { id: 3 },
         null,
-        null
+        null,
+        { id: 2 },
+        { id: 3 }
       ]);
     });
   });