How to calculate time duration in same day?

Curriculum Help
1

I want to get time duration in given time (“1970-01-01T12:21:19.000Z” - MSSQL time format) and current time. In same date (ignore the date).

Example :-
Given time = 12:25
Current Time = 14:30
Output = 2h 05min

2

Well, there are libraries, like moment.js that will do that for you.

If you want to do it yourself, I I would use the JS Date module to convert the to UTCs (the number of milliseconds since January 1, 1970). With that you can subtract them and do a little math to generate whatever output string you want.

3 
function timeDiffCalc(dateFuture, dateNow) {
    let diffInMilliSeconds = Math.abs(dateFuture - dateNow) / 1000;

    // calculate days
    const days = Math.floor(diffInMilliSeconds / 86400);
    diffInMilliSeconds -= days * 86400;
    console.log('calculated days', days);

    // calculate hours
    const hours = Math.floor(diffInMilliSeconds / 3600) % 24;
    diffInMilliSeconds -= hours * 3600;
    console.log('calculated hours', hours);

    // calculate minutes
    const minutes = Math.floor(diffInMilliSeconds / 60) % 60;
    diffInMilliSeconds -= minutes * 60;
    console.log('minutes', minutes);
    
    // calculate secounds
    var secd = ~~diffInMilliSeconds % 60;
    var seconds = Math.ceil(secd);

    let difference = '';
    if (days > 0) {
      difference += (days === 1) ? `${days} day, ` : `${days} days, `;
    }

    difference += (hours === 0 || hours === 1) ? `${hours} hour, ` : `${hours} hours, `;

    difference += (minutes === 0 || hours === 1) ? `${minutes} minutes ` : `${minutes} minutes `; 
    
    difference += ( hours === 1 || minutes === 1 ) ? `${seconds} secounds` : `${seconds} secounds`;
    

    return difference;
  }

const z = '2020/05/05'
const w = '13:12:00'
const l = '2020/05/05'
const o = '14:13:56'
const x = `${z} ${w}`
const y = `${l} ${o}`

const a = timeDiffCalc(new Date(x), new Date(y))
console.log(a);