my-website/static/scripts/relativetime.js

"use strict";

Array.from(document.getElementsByClassName("relative-timestamp")).forEach(
  function (timestamp) {
    if (timestamp?.dateTime) {
      timestamp.innerText = new Intl.DateTimeFormat(undefined, {
        dateStyle: "long",
        timeStyle: "short",
      }).format(new Date(timestamp.dateTime));
    }
  }
);