JAVASCRIPT

get date in specific timezone

function getTimeFromTimezone(offset) {  
  const currentDate = new Date() //get current time to calculate the UTC time
  let utc = currentDate.getTime() + (currentDate.getTimezoneOffset() * 60000) //calculates the UTC time
  let nd = new Date(utc + (3600000*offset)) // get the current timezone with the offset
  return nd
}

getTimeFromTimezone('+5.5').toLocaleString()
getTimeFromTimezone('-3').toLocaleString()

Get specific timezone time

function calcTime(city, offset) {

    d = new Date();

    utc = d.getTime() + (d.getTimezoneOffset() * 60000);

    nd = new Date(utc + (3600000*offset));

    return "The local time in " + city + " is " + nd.toLocaleString();

}

// get Bombay time
console.log(calcTime('Bombay', '+5.5'));

// get Singapore time
console.log(calcTime('Singapore', '+8'));

// get London time
console.log(calcTime('London', '+1'));