angularjs - Moment js counter -

hello every 1 i'm working on task uses moment js want make counter count min,sec , hours toggl.com counter have input field called start , 1 called end want subtract finish start , replace counter value , counter continue current value ex counter 0:00:10 , start is: 01:15 pm , end : 01:30 pm want subtract start end result value 00:15 value replaces current value of counter 0:00:10 0:15:00 counter start value , add seconds normal counter 0:15:01 , on please check toggl.com understand mean 2/ want if changed value of start value number 10 , if time pm consider 10 pm not 10 am code here can't that

  validate(val:string) {    let temp =this.starttime;    let parsedtime = moment(val, "hh:mm a");    if(parsedtime.isvalid()) {    this.starttime = parsedtime.format('hh:mm a')    } else {     this.starttime = "temp";     console.log("no");     }   } 

where val enterd value in start input field want if entered unexpected format replaces previous valid time not temp string tried this.starttime = this.starttime doesn't work want validation looks toggl.com please visit

and counter code own work don't expect wanted 1 behaviour

  startpause() {// when click on play button this.bs = moment(); this.starttime = this.bs.format('hh:mm a'); this.play = false; this.pause = true;  let sec= 0; let min = 0; let hour = 0;  this.countup = setinterval(() => {   if(sec === 59) {     min++;     sec = 0;   }else if(min > 59) {     hour++;     min = 0;   }else {     sec++;   }   this.timer = `${this.pad(hour)}:${this.pad(min)}:${this.pad(sec)}`; }, 1000);  } 

app.directive("timerup", function(util,$interval,$timeout){   return {     scope: { start: '=' },     require: "?ngmodel",     //template: "<input type='text' readonly class='form-control' ng-model='value' > ",     link: function(scope, element, attrs, ngmodel){          if (!ngmodel) return;          ngmodel.$render = function(){             scope.value = ngmodel.$modelvalue;         };          var timeout = 0;         $interval(function () {             if((scope.start)){                 //factory('util', [function () {                 return element.text(util.dhms(math.floor((new date().gettime() - scope.start.gettime())/ 1000)));             }         }, 1000);          function ontimeout() {             //timeout = timeout +1;             timeout++;         }     }   }; }); app.factory('util', [function () {     return {         dhms: function (t) {             var days, hours, minutes, seconds;             days = math.floor(t / 86400);             t -= days * 86400;             hours = math.floor(t / 3600) % 24;             t -= hours * 3600;             minutes = math.floor(t / 60) % 60;             t -= minutes * 60;             seconds = t % 60;             return [                 (days)? days + 'd': '',                 (hours)? hours + 'h':'',                 minutes + 'm',                 seconds + 's'             ].join(' ');         }     }; }]);  <span timerup ng-model="model" start="start"</span> 

start = initial date

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