feat(ngPluralize): add support for bind-once in count

Closes angular#10004

Author: gkalpak

src/ng/directive/ngPluralize.js

@@ -172,12 +172,13 @@
       </file>
     </example>
  */
-var ngPluralizeDirective = ['$locale', '$interpolate', function($locale, $interpolate) {
+var ngPluralizeDirective = ['$locale', '$interpolate', '$parse', function($locale, $interpolate, $parse) {
   var BRACE = /{}/g;
   return {
     restrict: 'EA',
     link: function(scope, element, attr) {
       var numberExp = attr.count,
+          oneTimeCount = (numberExp.charAt(0) === ':') && (numberExp.charAt(1) === ':'),
           whenExp = attr.$attr.when && element.attr(attr.$attr.when), // we have {{}} in attrs
           offset = attr.offset || 0,
           whens = scope.$eval(whenExp) || {},
@@ -198,20 +199,36 @@ var ngPluralizeDirective = ['$locale', '$interpolate', function($locale, $interp
             offset + endSymbol));
       });
 
-      scope.$watch(function ngPluralizeWatch() {
-        var value = parseFloat(scope.$eval(numberExp));
+      if (oneTimeCount) {
+        scope.$watch(numberExp, function ngPluralizeWatchOneTimeAction(newVal) {
+          var value = parseFloat(newVal);
+          var text = '';
 
-        if (!isNaN(value)) {
-          //if explicit number rule such as 1, 2, 3... is defined, just use it. Otherwise,
-          //check it against pluralization rules in $locale service
-          if (!(value in whens)) value = $locale.pluralCat(value - offset);
-           return whensExpFns[value](scope);
-        } else {
-          return '';
-        }
-      }, function ngPluralizeWatchAction(newVal) {
-        element.text(newVal);
-      });
+          if (!isNaN(value)) {
+            //if explicit number rule such as 1, 2, 3... is defined, just use it. Otherwise,
+            //check it against pluralization rules in $locale service
+            if (!(value in whens)) value = $locale.pluralCat(value - offset);
+            text = whensExpFns[value](scope);
+          }
+
+          element.text(text);
+        });
+      } else {
+        scope.$watch(function ngPluralizeWatch() {
+          var value = parseFloat(scope.$eval(numberExp));
+
+          if (!isNaN(value)) {
+            //if explicit number rule such as 1, 2, 3... is defined, just use it. Otherwise,
+            //check it against pluralization rules in $locale service
+            if (!(value in whens)) value = $locale.pluralCat(value - offset);
+             return whensExpFns[value](scope);
+          } else {
+            return '';
+          }
+        }, function ngPluralizeWatchAction(newVal) {
+          element.text(newVal);
+        });
+      }
     }
   };
 }];

test/ng/directive/ngPluralizeSpec.js

@@ -242,4 +242,36 @@ describe('ngPluralize', function() {
       });
     });
   });
+
+
+  describe('bind-once', function() {
+
+    it('should support bind-once in `count`', inject(function($compile, $rootScope) {
+      element = $compile(
+          '<ng:pluralize count="::email"' +
+                         "when=\"{'one': 'You have one new email'," +
+                                 "'other': 'You have {} new emails'}\">" +
+          '</ng:pluralize>')($rootScope);
+      elementAlt = $compile(
+          '<ng:pluralize count="::email" ' +
+                         "when-one='You have one new email' " +
+                         "when-other='You have {} new emails'>" +
+          '</ng:pluralize>')($rootScope);
+
+      $rootScope.email = 3;
+      $rootScope.$digest();
+      expect(element.text()).toBe('You have 3 new emails');
+      expect(elementAlt.text()).toBe('You have 3 new emails');
+
+      $rootScope.email = 2;
+      $rootScope.$digest();
+      expect(element.text()).toBe('You have 3 new emails');
+      expect(elementAlt.text()).toBe('You have 3 new emails');
+
+      $rootScope.email = 1;
+      $rootScope.$digest();
+      expect(element.text()).toBe('You have 3 new emails');
+      expect(elementAlt.text()).toBe('You have 3 new emails');
+    }));
+  });
 });