friendly.js

function friendly(arr) {
  var now = new Date();
  var fromDate = new Date(Date.parse(arr[0]));
  var toDate = new Date(Date.parse(arr[1]));
  var ord = [];
  if (sameYear(fromDate, now) && withinOneYear(fromDate, toDate)) {
    // Year should not be displayed at first date
    ord[0] = monthName(fromDate) + " " + nth(fromDate);
  } else {
    // All should be displayed at first date
    ord[0] = monthName(fromDate) + " " + nth(fromDate) + ", " + fromDate.getFullYear();
  }
  if (sameDay(fromDate, toDate)) {
    return ord;
  }
  if (sameMonth(fromDate, toDate)) {
    // Year and month should not be displayed at second date
    ord[1] = nth(toDate);
  } else if (withinOneYear(fromDate, toDate)) {
    // Month should not be displayed at second date
    ord[1] = monthName(toDate) + " " + nth(toDate);
  } else {
    // All information should be displayed at second date
    ord[1] = monthName(toDate) + " " + nth(toDate) + ", " + toDate.getFullYear();
  }
  return ord;
}

function sameDay(d1, d2) {
  // return ture if days, months and years match
  return (d1.getDate() === d2.getDate()) && sameMonth(d1, d2);
}

function sameMonth(d1, d2) {
  // return true if months and years match
  return (d1.getMonth() === d2.getMonth()) && sameYear(d1, d2);
}

function sameYear(d1, d2) {
  // return true if years match
  return d1.getYear() === d2.getYear();
}

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

function monthName(d) {
  return "January,February,March,April,May,June,July,August,September,October,November,December".split(",")[d.getMonth()];
}

function withinOneYear(d1, d2) {
  // return true if less than one year apart
  // NOTE: function doesn't work for leap years
  tmp = new Date(d2.getTime());
  tmp.setMonth(tmp.getMonth() - 12);
  return (d1 > tmp);
}

friendly(["2022-09-05", "2023-09-05"])