Convert frontend code to typescript (#31559)

None of the frontend js/ts files was touched besides these two commands
(edit: no longer true, I touched one file in
61105d0618
because of a deprecation that was not showing before the rename).

`tsc` currently reports 778 errors, so I have disabled it in CI as
planned.

Everything appears to work fine.

web_src/js/features/common-issue-list.ts

@@ -0,0 +1,68 @@
+import {isElemHidden, onInputDebounce, submitEventSubmitter, toggleElem} from '../utils/dom.ts';
+import {GET} from '../modules/fetch.ts';
+
+const {appSubUrl} = window.config;
+const reIssueIndex = /^(\d+)$/; // eg: "123"
+const reIssueSharpIndex = /^#(\d+)$/; // eg: "#123"
+const reIssueOwnerRepoIndex = /^([-.\w]+)\/([-.\w]+)#(\d+)$/;  // eg: "{owner}/{repo}#{index}"
+
+// if the searchText can be parsed to an "issue goto link", return the link, otherwise return empty string
+export function parseIssueListQuickGotoLink(repoLink, searchText) {
+  searchText = searchText.trim();
+  let targetUrl = '';
+  if (repoLink) {
+    // try to parse it in current repo
+    if (reIssueIndex.test(searchText)) {
+      targetUrl = `${repoLink}/issues/${searchText}`;
+    } else if (reIssueSharpIndex.test(searchText)) {
+      targetUrl = `${repoLink}/issues/${searchText.substr(1)}`;
+    }
+  } else {
+    // try to parse it for a global search (eg: "owner/repo#123")
+    const matchIssueOwnerRepoIndex = searchText.match(reIssueOwnerRepoIndex);
+    if (matchIssueOwnerRepoIndex) {
+      const [_, owner, repo, index] = matchIssueOwnerRepoIndex;
+      targetUrl = `${appSubUrl}/${owner}/${repo}/issues/${index}`;
+    }
+  }
+  return targetUrl;
+}
+
+export function initCommonIssueListQuickGoto() {
+  const goto = document.querySelector('#issue-list-quick-goto');
+  if (!goto) return;
+
+  const form = goto.closest('form');
+  const input = form.querySelector('input[name=q]');
+  const repoLink = goto.getAttribute('data-repo-link');
+
+  form.addEventListener('submit', (e) => {
+    // if there is no goto button, or the form is submitted by non-quick-goto elements, submit the form directly
+    let doQuickGoto = !isElemHidden(goto);
+    const submitter = submitEventSubmitter(e);
+    if (submitter !== form && submitter !== input && submitter !== goto) doQuickGoto = false;
+    if (!doQuickGoto) return;
+
+    // if there is a goto button, use its link
+    e.preventDefault();
+    window.location.href = goto.getAttribute('data-issue-goto-link');
+  });
+
+  const onInput = async () => {
+    const searchText = input.value;
+    // try to check whether the parsed goto link is valid
+    let targetUrl = parseIssueListQuickGotoLink(repoLink, searchText);
+    if (targetUrl) {
+      const res = await GET(`${targetUrl}/info`); // backend: GetIssueInfo, it only checks whether the issue exists by status code
+      if (res.status !== 200) targetUrl = '';
+    }
+    // if the input value has changed, then ignore the result
+    if (input.value !== searchText) return;
+
+    toggleElem(goto, Boolean(targetUrl));
+    goto.setAttribute('data-issue-goto-link', targetUrl);
+  };
+
+  input.addEventListener('input', onInputDebounce(onInput));
+  onInput();
+}