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/repo-home.ts

@@ -0,0 +1,147 @@
+import $ from 'jquery';
+import {stripTags} from '../utils.ts';
+import {hideElem, queryElemChildren, showElem} from '../utils/dom.ts';
+import {POST} from '../modules/fetch.ts';
+import {showErrorToast} from '../modules/toast.ts';
+
+const {appSubUrl} = window.config;
+
+export function initRepoTopicBar() {
+  const mgrBtn = document.querySelector('#manage_topic');
+  if (!mgrBtn) return;
+
+  const editDiv = document.querySelector('#topic_edit');
+  const viewDiv = document.querySelector('#repo-topics');
+  const topicDropdown = editDiv.querySelector('.ui.dropdown');
+  let lastErrorToast;
+
+  mgrBtn.addEventListener('click', () => {
+    hideElem(viewDiv);
+    showElem(editDiv);
+    topicDropdown.querySelector('input.search').focus();
+  });
+
+  document.querySelector('#cancel_topic_edit').addEventListener('click', () => {
+    lastErrorToast?.hideToast();
+    hideElem(editDiv);
+    showElem(viewDiv);
+    mgrBtn.focus();
+  });
+
+  document.querySelector('#save_topic').addEventListener('click', async (e) => {
+    lastErrorToast?.hideToast();
+    const topics = editDiv.querySelector('input[name=topics]').value;
+
+    const data = new FormData();
+    data.append('topics', topics);
+
+    const response = await POST(e.target.getAttribute('data-link'), {data});
+
+    if (response.ok) {
+      const responseData = await response.json();
+      if (responseData.status === 'ok') {
+        queryElemChildren(viewDiv, '.repo-topic', (el) => el.remove());
+        if (topics.length) {
+          const topicArray = topics.split(',');
+          topicArray.sort();
+          for (const topic of topicArray) {
+            // it should match the code in repo/home.tmpl
+            const link = document.createElement('a');
+            link.classList.add('repo-topic', 'ui', 'large', 'label');
+            link.href = `${appSubUrl}/explore/repos?q=${encodeURIComponent(topic)}&topic=1`;
+            link.textContent = topic;
+            mgrBtn.parentNode.insertBefore(link, mgrBtn); // insert all new topics before manage button
+          }
+        }
+        hideElem(editDiv);
+        showElem(viewDiv);
+      }
+    } else if (response.status === 422) {
+      // how to test: input topic like " invalid topic " (with spaces), and select it from the list, then "Save"
+      const responseData = await response.json();
+      lastErrorToast = showErrorToast(responseData.message, {duration: 5000});
+      if (responseData.invalidTopics.length > 0) {
+        const {invalidTopics} = responseData;
+        const topicLabels = queryElemChildren(topicDropdown, 'a.ui.label');
+        for (const [index, value] of topics.split(',').entries()) {
+          if (invalidTopics.includes(value)) {
+            topicLabels[index].classList.remove('green');
+            topicLabels[index].classList.add('red');
+          }
+        }
+      }
+    }
+  });
+
+  $(topicDropdown).dropdown({
+    allowAdditions: true,
+    forceSelection: false,
+    fullTextSearch: 'exact',
+    fields: {name: 'description', value: 'data-value'},
+    saveRemoteData: false,
+    label: {
+      transition: 'horizontal flip',
+      duration: 200,
+      variation: false,
+    },
+    apiSettings: {
+      url: `${appSubUrl}/explore/topics/search?q={query}`,
+      throttle: 500,
+      cache: false,
+      onResponse(res) {
+        const formattedResponse = {
+          success: false,
+          results: [],
+        };
+        const query = stripTags(this.urlData.query.trim());
+        let found_query = false;
+        const current_topics = [];
+        for (const el of queryElemChildren(topicDropdown, 'a.ui.label.visible')) {
+          current_topics.push(el.getAttribute('data-value'));
+        }
+
+        if (res.topics) {
+          let found = false;
+          for (const {topic_name} of res.topics) {
+            // skip currently added tags
+            if (current_topics.includes(topic_name)) {
+              continue;
+            }
+
+            if (topic_name.toLowerCase() === query.toLowerCase()) {
+              found_query = true;
+            }
+            formattedResponse.results.push({description: topic_name, 'data-value': topic_name});
+            found = true;
+          }
+          formattedResponse.success = found;
+        }
+
+        if (query.length > 0 && !found_query) {
+          formattedResponse.success = true;
+          formattedResponse.results.unshift({description: query, 'data-value': query});
+        } else if (query.length > 0 && found_query) {
+          formattedResponse.results.sort((a, b) => {
+            if (a.description.toLowerCase() === query.toLowerCase()) return -1;
+            if (b.description.toLowerCase() === query.toLowerCase()) return 1;
+            if (a.description > b.description) return -1;
+            if (a.description < b.description) return 1;
+            return 0;
+          });
+        }
+
+        return formattedResponse;
+      },
+    },
+    onLabelCreate(value) {
+      value = value.toLowerCase().trim();
+      this.attr('data-value', value).contents().first().replaceWith(value);
+      return $(this);
+    },
+    onAdd(addedValue, _addedText, $addedChoice) {
+      addedValue = addedValue.toLowerCase().trim();
+      $addedChoice[0].setAttribute('data-value', addedValue);
+      $addedChoice[0].setAttribute('data-text', addedValue);
+    },
+  });
+}