feat(dropdownToggle): add support for escape key

Closes #1558

src/dropdownToggle/dropdownToggle.js

@@ -10,6 +10,7 @@ angular.module('ui.bootstrap.dropdownToggle', [])
   this.open = function( dropdownScope ) {
     if ( !openScope ) {
       $document.bind('click', closeDropdown);
+      $document.bind('keydown', escapeKeyBind);
     }
 
     if ( openScope && openScope !== dropdownScope ) {
@@ -23,6 +24,7 @@ angular.module('ui.bootstrap.dropdownToggle', [])
     if ( openScope === dropdownScope ) {
       openScope = null;
       $document.unbind('click', closeDropdown);
+      $document.unbind('keydown', escapeKeyBind);
     }
   };
 
@@ -31,6 +33,12 @@ angular.module('ui.bootstrap.dropdownToggle', [])
       openScope.isOpen = false;
     });
   };
+
+  var escapeKeyBind = function( evt ) {
+    if ( evt.which === 27 ) {
+      closeDropdown();
+    }
+  };
 }])
 
 .controller('DropdownController', ['$scope', '$attrs', 'dropdownConfig', 'dropdownService', function($scope, $attrs, dropdownConfig, dropdownService) {

src/dropdownToggle/test/dropdownToggle.spec.js

@@ -14,6 +14,12 @@ describe('dropdownToggle', function() {
     elm.find('a').click();
   };
 
+  var triggerKeyDown = function (element, keyCode) {
+    var e = $.Event('keydown');
+    e.which = keyCode;
+    element.trigger(e);
+  };
+
   describe('basic', function() {
     function dropdown() {
       return $compile('<li class="dropdown"><a dropdown-toggle></a><ul><li>Hello</li></ul></li>')($rootScope);
@@ -38,6 +44,18 @@ describe('dropdownToggle', function() {
       expect(element.hasClass('open')).toBe(false);
     });
 
+    it('should close on escape key', function() {
+      clickDropdownToggle();
+      triggerKeyDown($document, 27);
+      expect(element.hasClass('open')).toBe(false);
+    });
+
+    it('should not close on backspace key', function() {
+      clickDropdownToggle();
+      triggerKeyDown($document, 8);
+      expect(element.hasClass('open')).toBe(true);
+    });
+
     it('should close on $location change', function() {
       clickDropdownToggle();
       expect(element.hasClass('open')).toBe(true);