How to dynamically change the Title of current menu element AngularJS (template in directive)

Question

I'm thinking how to solve this problem. Let's start:

I have a menu-bar (or navigation bar) in my site.

I'm creating it from JSON file, I'm using an AngularJS directive and the template to create it:

JSON file:

{
    "mainmenu": [
        {
            "id": "bananas",
            "title": "Bananas",
            "href": "#/bananas",
            "li-class": "menu-element"
        },
        {
            "id": "apples",
            "title": "Apples",
            "li-class": "dropdown"
            "submenu": [
                {
                    "id": "apple-lot",
                    "title": "Apples lots",
                    "href": "#/apples/lot"                  
                },
                {
                    "id": "apple-series",
                    "title": "Apples series",
                    "href": "#/apples/series"
                }               
            ]
        },
        {
            "id": "cherries",
            "title": "Cherries",
            "href": "#/cherries",
            "li-class": "menu-element"
        }
    ]
}

My AngularJS directive with template:

angular.module('dynamic-menu').directive('menuTemplate', function () {
    return {
        restrict: 'E',
        template: "<nav class=\"navbar navbar-inverse navbar-fixed-top\" role=\"navigation\" id=\"nav-bar\" style=\"margin-bottom: 0.5%\">"
                        + "<div class=\"container-fluid\">"
                            + "<div class=\"navbar-header\">"
                                + "<span class=\"navbar-brand\">TITLE</span>"
                            + "</div>"
                            + "<div class=\"collapse navbar-collapse\">"
                                + "<span class=\"navbar-brand\">"
                                        + "<ul class=\"nav navbar-nav\">"
                                            + "<li ng-repeat=\"item in mainmenu\">"
                                                + "<a href=\"{{item.href}}\">{{item.title}}</a>"
                                            +"</li>"
                                        +"</ul> <!-- /.nav navbar-nav -->"
                                    +"</span> <!-- /.navbar-brand -->"
                                +"</div> <!-- /.navbar-collapse-->"
                            +"</div> <!-- /.container-fluid-->"
                        +"</nav>"
           };
}]);

And AngularJS controller:

angular.module('dynamic-menu').controller('dynamicMenuCtrl', ['$scope', '$http', function ($scope, $http) {
    $http.get('MenuItems.json').success(function (data) {

        $scope.mainmenu = data;
    });

The problem is - how to dynamically change the TITLE?

This line in my AngularJS directive:

+ "<span class=\"navbar-brand\">TITLE</span>"

Maybe I can add something to my JSON file and check in some way is there a class assigned for the active-menu-element? (for ex. <li class="menu-item-active">) or how?

Here is Plunker - and there is a Title which I want to change dynamically in my template

http://plnkr.co/edit/U1xG2E4ys7SGz7WxBtvq?p=preview

I have to use the directive

EDIT: What I want to achieve:

On the main page I want to have title fruits, when I'm on the sub-menu Bananas I want to display the title Bananas

Answer 1

json:

{
    "title": "some title",
    "mainmenu": [
        {
            "id": "bananas",
            "title": "Bananas",
            "href": "#/bananas",
            "li-class": "menu-element"
        },
        {
            "id": "apples",
            "title": "Apples",
            "li-class": "dropdown"
            "submenu": [
                {
                    "id": "apple-lot",
                    "title": "Apples lots",
                    "href": "#/apples/lot"                  
                },
                {
                    "id": "apple-series",
                    "title": "Apples series",
                    "href": "#/apples/series"
                }               
            ]
        },
        {
            "id": "cherries",
            "title": "Cherries",
            "href": "#/cherries",
            "li-class": "menu-element"
        }
    ]
}

in template

"<span class=\"navbar-brand\">{{title}}</span>"

js: angular.module('dynamic-menu').controller('dynamicMenuCtrl', ['$scope', '$http',

function ($scope, $http) {
    $http.get('MenuItems.json').success(function (data) {

        $scope.mainmenu = data;
        $scope.title = data.title;
    });

http://plnkr.co/edit/LvObdZB72umVPCfTsVg1?p=preview