how to subtract two time string (HH:MM) in javascript

how to subtract two time string (HH:MM) in javascript

var time1= "03:01";
var time2= "01:19";

function strToMins(t) {
  var s = t.split(":");
  return Number(s[0]) * 60 + Number(s[1]);
}

function minsToStr(t) {
  return Math.trunc(t / 60)+':'+('00' + t % 60).slice(-2);
}

var result = minsToStr( strToMins(time1) - strToMins(time2) );
console.log(result);