JavaScript new Date Ordinal (st, nd, rd, th)

const nth = function(d) {
  if (d > 3 && d < 21) return 'th';
  switch (d % 10) {
    case 1:  return "st";
    case 2:  return "nd";
    case 3:  return "rd";
    default: return "th";
  }
}

// test code

const fortnightAway = new Date(+new Date + 12096e5);
const date = fortnightAway.getDate();
const month = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"][fortnightAway.getMonth()];

document.getElementById("date").innerHTML = `In two weeks it will be the ${date}<sup>${nth(date)}</sup> of ${month} ${fortnightAway.getFullYear()}`;

// test
const dates = [...Array(32).keys()].slice(1).map(i => `${i}${nth(i)}`)
console.log(dates.join(", "))

sup {
  font-size: x-small
}

<span id="date"></span>

const nth = function(d) {
  const dString = String(d);
  const last = +dString.slice(-2);
  if (last > 3 && last < 21) return 'th';
  switch (last % 10) {
    case 1:  return "st";
    case 2:  return "nd";
    case 3:  return "rd";
    default: return "th";
  }
}

// test
const numbers = [...Array(1225).keys()].map(i => `${i}${nth(i)}`)
console.log(numbers.join(", "))

sup {
  font-size: x-small
}

<span id="date"></span>