feat(tab): allow active index string

Allow Tab index to be a string

Closes #5687
Closes #5577
Closes #5713

Author: vadim-p

Diff for: src/tabs/docs/readme.md

@@ -5,7 +5,7 @@ AngularJS version of the tabs directive.
 * `active`
   <i class="glyphicon glyphicon-eye-open"></i>
   _(Default: `Index of first tab`)_ -
-  Active index of tab. Setting this to an existing tab index will make that tab active.
+  Active index of tab. Setting this to an existing tab index will make that tab active. Can be a number or string.
 
 * `justified`
   <small class="badge">$</small>

Diff for: src/tabs/tabs.js

@@ -73,7 +73,7 @@ angular.module('ui.bootstrap.tabs', [])
   };
 
   $scope.$watch('tabset.active', function(val) {
-    if (angular.isNumber(val) && val !== oldIndex) {
+    if ((angular.isNumber(val) || angular.isString(val)) && val !== oldIndex) {
       ctrl.select(findTabIndex(val));
     }
   });
@@ -85,7 +85,7 @@ angular.module('ui.bootstrap.tabs', [])
 
   function findTabIndex(index) {
     for (var i = 0; i < ctrl.tabs.length; i++) {
-      if (ctrl.tabs[i].index === index) {
+      if (ctrl.tabs[i].index === +index) {
         return i;
       }
     }

Diff for: src/tabs/test/tabs.spec.js

@@ -168,6 +168,16 @@ describe('tabs', function() {
       expect(titles().length).toBe(scope.tabs.length);
       expectTabActive(scope.tabs[2]);
     });
+
+    it("should watch active state", function() {
+      var controller = elm.controller('uibTabset');
+      spyOn(controller, "select");
+      expect(titles().length).toBe(scope.tabs.length);
+      expectTabActive(scope.tabs[2]);
+      scope.active = "7";
+      scope.$apply();
+      expect(controller.select).toHaveBeenCalledWith(3);
+    });
   });
 
   describe('without active binding and index attributes', function() {