angular 倒计时15 minute的方法封装

function countDownTime (){
    var m = 14, s = 60;
    $scope.date = '15:00';
    $interval(function run() {
        s--;
        if (s < 0) {
            m--;
            s = 59;
        }
        if (s < 10) {
            $scope.date = m + ':' + '0' + s;
        }
        if (m < 10) {
            $scope.date = '0' + m + ':' + s;
            if (m < 0) {
                s = 0;
                m = 0;
            }
        } else {
            if (s >= 10) {
                $scope.date = m + ':' + s;
            } else {
                $scope.date = m + ':' + '0' + s;
            }
        }
        if (m < 10 && s < 10) {
            $scope.date = '0' + m + ':' + '0' + s;
            if (m < 0 && s < 0) {
                s = 0;
                m = 0;
            }
        }
    }, 1000);

countDownTime（）；