The way I did , it works!
Angular code
var app = angular.module('counter', []);_x000D_
_x000D_
app.controller('MainCtrl', function($scope, $interval) {_x000D_
var decreamentCountdown = function() {_x000D_
$scope.countdown -= 1;_x000D_
if ($scope.countdown < 1) {_x000D_
$scope.message = "timed out";_x000D_
}_x000D_
};_x000D_
var startCountDown = function() {_x000D_
$interval(decreamentCountdown, 1000, $scope.countdown)_x000D_
};_x000D_
$scope.countdown = 100;_x000D_
startCountDown();_x000D_
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.10/angular.min.js"></script>_x000D_
_x000D_
_x000D_
_x000D_
<body ng-app="counter" ng-controller="MainCtrl">_x000D_
{{countdown}} {{message}}_x000D_
</body>
_x000D_