javascript - Reevaluate filter on timer in AngularJS -

i have filter use display relative time i.e. 5 mins ago. want able make filter (or write directive) re-evaluate every minute. how can this?

js filter

m.filter('relativetime', function () {     return function (input, showago) {         if (typeof showago == "undefined") {             showago = true;         }          var datemoment = input;         if (typeof input == "string") {             datemoment = moment(input);         }          return datemoment.fromnow(showago);     }; }); 

html

<span class="relativetime">{{activity.time | relativetime }}</span> 

although it's possible create stateful filter, documentation strongly advices make stateless , idempotent filters. that's why directive better idea here.

the principle simple: when directive compiled, create timer refresh value every minute. $interval service perfect goal. however, stated documentation, don't forget destroy when don't need more.

myapp.directive('relativetime', function ($interval) {     return {         scope: {             time: '=',         },         template: '<div>{{relativetime}} secondes ago.</div>',         link: function ($scope) {             $scope.relativetime = 0;              var intervalpromise = $interval(function () {                 ++$scope.relativetime;             }, 1000);              $scope.$watch('time', function (time) {                 var currenttime = new date();                 $scope.relativetime = math.round((currenttime.gettime() - time.gettime()) / 1000);             });              $scope.$on('$destroy', function () {                 $interval.cancel(intervalpromise);             });         },     }; }); 

fiddle

for demonstration purposes, directive simple , updated every second. it's shouldn't difficult adapt use case , in particular date.fromnow() function.