feat(tabs): pass the selected tab index to onDeselect

-  Add the index of the tab the user attempted to open to the onDeselect call, which allows the user to directed to the selected tab
after some work is performed.

- Closes #5820

src/tabs/docs/readme.md

@@ -33,7 +33,7 @@ AngularJS version of the tabs directive.
 
 * `deselect()`
   <small class="badge">$</small> -
-  An optional expression called when tab is deactivated. Supports $event in template for expression. You may call `$event.preventDefault()` in this event handler to prevent a tab change from occurring.
+  An optional expression called when tab is deactivated. Supports `$event` and `$selectedIndex` in template for expression. You may call `$event.preventDefault()` in this event handler to prevent a tab change from occurring. The `$selectedIndex` can be used to determine which tab was attempted to be opened.
 
 * `disable`
   <small class="badge">$</small>

src/tabs/tabs.js

@@ -11,7 +11,8 @@ angular.module('ui.bootstrap.tabs', [])
       var previousSelected = ctrl.tabs[previousIndex];
       if (previousSelected) {
         previousSelected.tab.onDeselect({
-          $event: evt
+          $event: evt,
+          $selectedIndex: index
         });
         if (evt && evt.isDefaultPrevented()) {
           return;

src/tabs/test/tabs.spec.js

@@ -46,14 +46,14 @@ describe('tabs', function() {
       };
       elm = $compile([
         '<uib-tabset class="hello" data-pizza="pepperoni" active="active">',
-        '  <uib-tab index="1" heading="First Tab {{first}}" classes="{{firstClass}}" select="selectFirst($event)" deselect="deselectFirst($event)">',
+        '  <uib-tab index="1" heading="First Tab {{first}}" classes="{{firstClass}}" select="selectFirst($event)" deselect="deselectFirst($event, $selectedIndex)">',
         '    first content is {{first}}',
         '  </uib-tab>',
-        '  <uib-tab index="2" classes="{{secondClass}}" select="selectSecond($event)" deselect="deselectSecond($event)">',
+        '  <uib-tab index="2" classes="{{secondClass}}" select="selectSecond($event)" deselect="deselectSecond($event, $selectedIndex)">',
         '    <uib-tab-heading><b>Second</b> Tab {{second}}</uib-tab-heading>',
         '    second content is {{second}}',
         '  </uib-tab>',
-        '  <uib-tab index="3" classes="{{thirdClass}}" deselect="deselectThird($event)">',
+        '  <uib-tab index="3" classes="{{thirdClass}}" deselect="deselectThird($event, $selectedIndex)">',
         '    <uib-tab-heading><b>Second</b> Tab {{third}}</uib-tab-heading>',
         '    third content is {{third}}',
         '  </uib-tab>',
@@ -118,12 +118,15 @@ describe('tabs', function() {
       titles().eq(1).find('> a').click();
       expect(scope.deselectFirst).toHaveBeenCalled();
       expect(scope.deselectFirst.calls.argsFor(0)[0].target).toBe(titles().eq(1).find('> a')[0]);
+      expect(scope.deselectFirst.calls.argsFor(0)[1]).toBe(1);
       titles().eq(0).find('> a').click();
       expect(scope.deselectSecond).toHaveBeenCalled();
       expect(scope.deselectSecond.calls.argsFor(0)[0].target).toBe(titles().eq(0).find('> a')[0]);
+      expect(scope.deselectSecond.calls.argsFor(0)[1]).toBe(0);
       titles().eq(1).find('> a').click();
       expect(scope.deselectFirst.calls.count()).toBe(2);
       expect(scope.deselectFirst.calls.argsFor(1)[0].target).toBe(titles().eq(1).find('> a')[0]);
+      expect(scope.deselectFirst.calls.argsFor(1)[1]).toBe(1);
     });
 
     it('should prevent tab deselection when $event.preventDefault() is called', function() {