[angularjs] How to highlight a current menu item?

I just wrote a directive for this.

Usage:

<ul class="nav navbar-nav">
  <li active><a href="#/link1">Link 1</a></li>
  <li active><a href="#/link2">Link 2</a></li>
</ul>

Implementation:

angular.module('appName')
  .directive('active', function ($location, $timeout) {
    return {
      restrict: 'A',
      link: function (scope, element, attrs) {
        // Whenever the user navigates to a different page...
        scope.$on('$routeChangeSuccess', function () {
          // Defer for other directives to load first; this is important
          // so that in case other directives are used that this directive
          // depends on, such as ng-href, the href is evaluated before
          // it's checked here.
          $timeout(function () {
            // Find link inside li element
            var $link = element.children('a').first();

            // Get current location
            var currentPath = $location.path();

            // Get location the link is pointing to
            var linkPath = $link.attr('href').split('#').pop();

            // If they are the same, it means the user is currently
            // on the same page the link would point to, so it should
            // be marked as such
            if (currentPath === linkPath) {
              $(element).addClass('active');
            } else {
              // If they're not the same, a li element that is currently
              // marked as active needs to be "un-marked"
              element.removeClass('active');
            }
          });
        });
      }
    };
  });

Tests:

'use strict';

describe('Directive: active', function () {

  // load the directive's module
  beforeEach(module('appName'));

  var element,
      scope,
      location,
      compile,
      rootScope,
      timeout;

  beforeEach(inject(function ($rootScope, $location, $compile, $timeout) {
    scope = $rootScope.$new();
    location = $location;
    compile = $compile;
    rootScope = $rootScope;
    timeout = $timeout;
  }));

  describe('with an active link', function () {
    beforeEach(function () {
      // Trigger location change
      location.path('/foo');
    });

    describe('href', function () {
      beforeEach(function () {
        // Create and compile element with directive; note that the link
        // is the same as the current location after the location change.
        element = angular.element('<li active><a href="#/foo">Foo</a></li>');
        element = compile(element)(scope);

        // Broadcast location change; the directive waits for this signal
        rootScope.$broadcast('$routeChangeSuccess');

        // Flush timeout so we don't have to write asynchronous tests.
        // The directive defers any action using a timeout so that other
        // directives it might depend on, such as ng-href, are evaluated
        // beforehand.
        timeout.flush();
      });

      it('adds the class "active" to the li', function () {
        expect(element.hasClass('active')).toBeTruthy();
      });
    });

    describe('ng-href', function () {
      beforeEach(function () {
        // Create and compile element with directive; note that the link
        // is the same as the current location after the location change;
        // however this time with an ng-href instead of an href.
        element = angular.element('<li active><a ng-href="#/foo">Foo</a></li>');
        element = compile(element)(scope);

        // Broadcast location change; the directive waits for this signal
        rootScope.$broadcast('$routeChangeSuccess');

        // Flush timeout so we don't have to write asynchronous tests.
        // The directive defers any action using a timeout so that other
        // directives it might depend on, such as ng-href, are evaluated
        // beforehand.
        timeout.flush();
      });

      it('also works with ng-href', function () {
        expect(element.hasClass('active')).toBeTruthy();
      });
    });
  });

  describe('with an inactive link', function () {
    beforeEach(function () {
      // Trigger location change
      location.path('/bar');

      // Create and compile element with directive; note that the link
      // is the NOT same as the current location after the location change.
      element = angular.element('<li active><a href="#/foo">Foo</a></li>');
      element = compile(element)(scope);

      // Broadcast location change; the directive waits for this signal
      rootScope.$broadcast('$routeChangeSuccess');

      // Flush timeout so we don't have to write asynchronous tests.
      // The directive defers any action using a timeout so that other
      // directives it might depend on, such as ng-href, are evaluated
      // beforehand.
      timeout.flush();
    });

    it('does not add the class "active" to the li', function () {
      expect(element.hasClass('active')).not.toBeTruthy();
    });
  });

  describe('with a formerly active link', function () {
    beforeEach(function () {
      // Trigger location change
      location.path('/bar');

      // Create and compile element with directive; note that the link
      // is the same as the current location after the location change.
      // Also not that the li element already has the class "active".
      // This is to make sure that a link that is active right now will
      // not be active anymore when the user navigates somewhere else.
      element = angular.element('<li class="active" active><a href="#/foo">Foo</a></li>');
      element = compile(element)(scope);

      // Broadcast location change; the directive waits for this signal
      rootScope.$broadcast('$routeChangeSuccess');

      // Flush timeout so we don't have to write asynchronous tests.
      // The directive defers any action using a timeout so that other
      // directives it might depend on, such as ng-href, are evaluated
      // beforehand.
      timeout.flush();
    });

    it('removes the "active" class from the li', function () {
      expect(element.hasClass('active')).not.toBeTruthy();
    });
  });
});