Edits the SubredditPurge mail to have links and an "Open all" button, autofills SubredditPurge info on the ban page if SubredditPurge hasn't been banned yet

subredditpurge-helper.user.js

// ==UserScript==
// @name        SubredditPurge helper - reddit.com
// @namespace   Rebane
// @match       https://*.reddit.com/r/*/about/banned/
// @match       https://*.reddit.com/message/messages/*
// @grant       none
// @version     1.0.1
// @author      Rebane
// @description Edits the SubredditPurge mail to have links and an "Open all" button, autofills SubredditPurge info on the ban page if SubredditPurge hasn't been banned yet (2023-11-07)
// ==/UserScript==

window.onload = () => {
  // Ban page
  if (document.location.href.endsWith("/banned/") && !document.querySelector("a[href='https://www.reddit.com/user/SubredditPurge/']")) {
    document.querySelector("#name").value = "SubredditPurge";
    document.querySelector("[name='ban_reason']").value = "other";
    document.querySelector("#note").value = "Prevent subreddit from getting purged";
  }
  // Message
  const sender = document.querySelector(".sender");
  if (sender?.innerText?.startsWith("reddit\n")) {
    const msgMarkdown = sender.parentNode.parentNode.parentNode.querySelector(".md");
    msgMarkdown.querySelectorAll("li").forEach(e => {
      const subredditName = e.childNodes[0].textContent.trim();
      const banLink = document.createElement("a");
      banLink.innerText = subredditName;
      banLink.href = `https://www.reddit.com/r/${subredditName}/about/banned/`;
      banLink.classList.add("banLink");
      banLink.setAttribute('target', '_blank');
      e.replaceChild(banLink, e.childNodes[0]);
    });
    const openAllBtn = document.createElement("button");
    openAllBtn.innerText = "Open all subs";
    openAllBtn.onclick = () => {
      try {
        document.querySelectorAll(".banLink").forEach(e => e.click());
      } catch {
        alert("Error, make sure you have allowed popups from reddit");
      }
    };
    msgMarkdown.querySelector("li").parentNode.insertBefore(openAllBtn, msgMarkdown.querySelector("li"));
  }
}