Time Calculation in Java Script

// a_value = "04:22:00"; hh:mm:ss
// b_value = "06:13:10"; hh:mm:ss

function time_calculation(a_value, b_value)
{
  var hour = 0;
  var minute = 0;
  var second = 0;

  var splitTime1 = a_value.toString().split(':');
  var splitTime2 = b_value.toString().split(':');

  hour = parseInt(check_Int(splitTime1[0]))+parseInt(check_Int(splitTime2[0]));
  minute = parseInt(check_Int(splitTime1[1]))+parseInt(check_Int(splitTime2[1]));
  hour = hour + minute/60;
  hour = Math.floor(hour); // Extra Add
  minute = minute%60;
  second = parseInt(check_Int(splitTime1[2]))+parseInt(check_Int(splitTime2[2]));
  minute = minute + second/60;
  second = second%60;
  const zeroPad = (num, places) => String(num).padStart(places, '0');

  return zeroPad(hour, 2)+':'+zeroPad(minute, 2)+':'+zeroPad(second, 2);
}

function check_Int(argument)
{
  if(argument % 1 === 0){
    return argument;
  }else{
    return 0;
  }
}