gcg-website/static/admin/previews/field-previews/date-preview.js

const DatePreview = ({ value }) =>
  h(
    "p",
    {},
    new Intl.DateTimeFormat("de-DE", {
      year: "numeric",
      month: "2-digit",
      day: "2-digit",
      hour12: false,
    }).format(new Date(value))
  );

export default DatePreview;