content/redirect.html

---js
{
  pagination: {
    data: "collections.all",
    size: 1,
    alias: "redirect",
    before: function (data) {
      const all = data.reduce((redirects, page) => {
        if (Array.isArray(page.data.redirect_from)) {
          for (let url of page.data.redirect_from) {
            redirects.push({ to: page.url, from: url });
          }
        } else if (typeof page.data.redirect_from === 'string') {
          redirects.push({ to: page.url, from: page.data.redirect_from });
        }
        if (page.data.redirect_from) {
        }
        return (redirects);
      }, []);

      return all.filter(({ to, from })=> to !== from);
    },
    addAllPagesToCollections: false,
  },
  permalink: "{{ redirect.from }}/index.html",
  eleventyExcludeFromCollections: true,
}
---

<!DOCTYPE html>
<html lang="en-US">
  <head>
    <meta charset="utf-8" />
    <title>Redirecting&hellip;</title>
    <link rel="canonical" href="{{ redirect.to | url }}" />
    <script>
      location = "{{ redirect.to | url }}"
    </script>
    <meta name="rel-path" content="{{ redirect.to | url }}" />
    <meta http-equiv="refresh" content="0; url={{ redirect.to | url }}" />
    <meta name="robots" content="noindex" />
  </head>
  <body>
    <h1>Redirecting&hellip;</h1>
    <a href="{{ redirect.to | url }}">Click here if you are not redirected.</a>
  </body>
</html>