MinutesCounter.js

const calcMinutes = (time="12:30 AM-07:30 PM") => {

  const _time = time.split("-")

  const lastMeridian = _time[1].slice(-2)
  let firstDate = "2022-01-01"
  let lastDate = "2022-01-01"
  if(lastMeridian=="AM"){
    firstDate = "2022-01-02"
  }
const ageDifMs = new Date(firstDate+' '+_time[1]).getTime() - new Date(lastDate+' '+_time[0]).getTime();
const ageDate = new Date(ageDifMs);
const age = Math.abs(ageDate.getUTCFullYear() - 1970);
console.log(ageDifMs/60000)
}

calcMinutes()

// console.log((ageDifMs/3600)/3600)