Not able to update digital clock

I have to display respective time zone in digital format. The clock is displayed but it only updates after refreshing the page. Below is the code I used. Below is my javascript code:

time: function() {
    var zone = _.date.fleetTimeZone();
    return moment().zone(zone).format('h:mm:ss a');
}.property('DS.session.last_fleet_interacted'),

Below is my handlebars:

<div class="time">{{time}}</div>