Describe the time difference between a timestamp and now

get-time-difference.js

function getTimeDifference(timestamp) {
  let now = new Date();
  let difference = now.getTime() - timestamp;
  let seconds = Math.floor(difference / 1000);
  let minutes = Math.floor(seconds / 60);
  let hours = Math.floor(minutes / 60);
  let days = Math.floor(hours / 24);

  let time = "";
  if (days > 0) {
    time = days + "d ago";
  } else if (hours > 0) {
    time = hours + "hr ago";
  } else if (minutes > 0) {
    time = minutes + "min ago";
  } else {
    time = seconds + "sec ago";
  }

  return time;
}