diff --git a/tests/e2e/utils_e2e.ts b/tests/e2e/utils_e2e.ts
index 14ec836600..3e92e0d3c2 100644
--- a/tests/e2e/utils_e2e.ts
+++ b/tests/e2e/utils_e2e.ts
@@ -1,12 +1,13 @@
 import {expect} from '@playwright/test';
 import {env} from 'node:process';
+import type {Browser, Page, WorkerInfo} from '@playwright/test';
 
 const ARTIFACTS_PATH = `tests/e2e/test-artifacts`;
 const LOGIN_PASSWORD = 'password';
 
 // log in user and store session info. This should generally be
 //  run in test.beforeAll(), then the session can be loaded in tests.
-export async function login_user(browser, workerInfo, user) {
+export async function login_user(browser: Browser, workerInfo: WorkerInfo, user: string) {
   // Set up a new context
   const context = await browser.newContext();
   const page = await context.newPage();
@@ -17,8 +18,8 @@ export async function login_user(browser, workerInfo, user) {
   expect(response?.status()).toBe(200); // Status OK
 
   // Fill out form
-  await page.type('input[name=user_name]', user);
-  await page.type('input[name=password]', LOGIN_PASSWORD);
+  await page.locator('input[name=user_name]').fill(user);
+  await page.locator('input[name=password]').fill(LOGIN_PASSWORD);
   await page.click('form button.ui.primary.button:visible');
 
   await page.waitForLoadState('networkidle'); // eslint-disable-line playwright/no-networkidle
@@ -31,7 +32,7 @@ export async function login_user(browser, workerInfo, user) {
   return context;
 }
 
-export async function load_logged_in_context(browser, workerInfo, user) {
+export async function load_logged_in_context(browser: Browser, workerInfo: WorkerInfo, user: string) {
   let context;
   try {
     context = await browser.newContext({storageState: `${ARTIFACTS_PATH}/state-${user}-${workerInfo.workerIndex}.json`});
@@ -43,7 +44,7 @@ export async function load_logged_in_context(browser, workerInfo, user) {
   return context;
 }
 
-export async function save_visual(page) {
+export async function save_visual(page: Page) {
   // Optionally include visual testing
   if (env.VISUAL_TEST) {
     await page.waitForLoadState('networkidle'); // eslint-disable-line playwright/no-networkidle
diff --git a/tsconfig.json b/tsconfig.json
index c41f9646d6..78b74a3d3c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -23,6 +23,7 @@
     "stripInternal": true,
     "strict": false,
     "strictFunctionTypes": true,
+    "noImplicitAny": true,
     "noImplicitThis": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
diff --git a/web_src/js/components/DashboardRepoList.vue b/web_src/js/components/DashboardRepoList.vue
index 40ecbba5e3..876292fc94 100644
--- a/web_src/js/components/DashboardRepoList.vue
+++ b/web_src/js/components/DashboardRepoList.vue
@@ -130,12 +130,12 @@ export default defineComponent({
   },
 
   methods: {
-    changeTab(t) {
-      this.tab = t;
+    changeTab(tab: string) {
+      this.tab = tab;
       this.updateHistory();
     },
 
-    changeReposFilter(filter) {
+    changeReposFilter(filter: string) {
       this.reposFilter = filter;
       this.repos = [];
       this.page = 1;
@@ -218,7 +218,7 @@ export default defineComponent({
       this.searchRepos();
     },
 
-    changePage(page) {
+    changePage(page: number) {
       this.page = page;
       if (this.page > this.finalPage) {
         this.page = this.finalPage;
@@ -256,7 +256,7 @@ export default defineComponent({
       }
 
       if (searchedURL === this.searchURL) {
-        this.repos = json.data.map((webSearchRepo) => {
+        this.repos = json.data.map((webSearchRepo: any) => {
           return {
             ...webSearchRepo.repository,
             latest_commit_status_state: webSearchRepo.latest_commit_status?.State, // if latest_commit_status is null, it means there is no commit status
@@ -264,7 +264,7 @@ export default defineComponent({
             locale_latest_commit_status_state: webSearchRepo.locale_latest_commit_status,
           };
         });
-        const count = response.headers.get('X-Total-Count');
+        const count = Number(response.headers.get('X-Total-Count'));
         if (searchedQuery === '' && searchedMode === '' && this.archivedFilter === 'both') {
           this.reposTotalCount = count;
         }
@@ -275,7 +275,7 @@ export default defineComponent({
       }
     },
 
-    repoIcon(repo) {
+    repoIcon(repo: any) {
       if (repo.fork) {
         return 'octicon-repo-forked';
       } else if (repo.mirror) {
@@ -298,7 +298,7 @@ export default defineComponent({
       return commitStatus[status].color;
     },
 
-    reposFilterKeyControl(e) {
+    reposFilterKeyControl(e: KeyboardEvent) {
       switch (e.key) {
         case 'Enter':
           document.querySelector<HTMLAnchorElement>('.repo-owner-name-list li.active a')?.click();
diff --git a/web_src/js/components/DiffCommitSelector.vue b/web_src/js/components/DiffCommitSelector.vue
index 840acd4b51..16760d1cb1 100644
--- a/web_src/js/components/DiffCommitSelector.vue
+++ b/web_src/js/components/DiffCommitSelector.vue
@@ -4,6 +4,22 @@ import {SvgIcon} from '../svg.ts';
 import {GET} from '../modules/fetch.ts';
 import {generateAriaId} from '../modules/fomantic/base.ts';
 
+type Commit = {
+  id: string,
+  hovered: boolean,
+  selected: boolean,
+  summary: string,
+  committer_or_author_name: string,
+  time: string,
+  short_sha: string,
+}
+
+type CommitListResult = {
+  commits: Array<Commit>,
+  last_review_commit_sha: string,
+  locale: Record<string, string>,
+}
+
 export default defineComponent({
   components: {SvgIcon},
   data: () => {
@@ -16,9 +32,9 @@ export default defineComponent({
       locale: {
         filter_changes_by_commit: el.getAttribute('data-filter_changes_by_commit'),
       } as Record<string, string>,
-      commits: [],
+      commits: [] as Array<Commit>,
       hoverActivated: false,
-      lastReviewCommitSha: null,
+      lastReviewCommitSha: '',
       uniqueIdMenu: generateAriaId(),
       uniqueIdShowAll: generateAriaId(),
     };
@@ -71,7 +87,7 @@ export default defineComponent({
       if (event.key === 'ArrowDown' || event.key === 'ArrowUp') {
         const item = document.activeElement; // try to highlight the selected commits
         const commitIdx = item?.matches('.item') ? item.getAttribute('data-commit-idx') : null;
-        if (commitIdx) this.highlight(this.commits[commitIdx]);
+        if (commitIdx) this.highlight(this.commits[Number(commitIdx)]);
       }
     },
     onKeyUp(event: KeyboardEvent) {
@@ -87,7 +103,7 @@ export default defineComponent({
         }
       }
     },
-    highlight(commit) {
+    highlight(commit: Commit) {
       if (!this.hoverActivated) return;
       const indexSelected = this.commits.findIndex((x) => x.selected);
       const indexCurrentElem = this.commits.findIndex((x) => x.id === commit.id);
@@ -125,10 +141,11 @@ export default defineComponent({
         }
       });
     },
+
     /** Load the commits to show in this dropdown */
     async fetchCommits() {
       const resp = await GET(`${this.issueLink}/commits/list`);
-      const results = await resp.json();
+      const results = await resp.json() as CommitListResult;
       this.commits.push(...results.commits.map((x) => {
         x.hovered = false;
         return x;
@@ -166,7 +183,7 @@ export default defineComponent({
      * the diff from beginning of PR up to the second clicked commit is
      * opened
      */
-    commitClickedShift(commit) {
+    commitClickedShift(commit: Commit) {
       this.hoverActivated = !this.hoverActivated;
       commit.selected = true;
       // Second click -> determine our range and open links accordingly
diff --git a/web_src/js/components/DiffFileList.vue b/web_src/js/components/DiffFileList.vue
index 792a1aefac..6570c92781 100644
--- a/web_src/js/components/DiffFileList.vue
+++ b/web_src/js/components/DiffFileList.vue
@@ -18,14 +18,14 @@ function toggleFileList() {
 }
 
 function diffTypeToString(pType: number) {
-  const diffTypes = {
-    1: 'add',
-    2: 'modify',
-    3: 'del',
-    4: 'rename',
-    5: 'copy',
+  const diffTypes: Record<string, string> = {
+    '1': 'add',
+    '2': 'modify',
+    '3': 'del',
+    '4': 'rename',
+    '5': 'copy',
   };
-  return diffTypes[pType];
+  return diffTypes[String(pType)];
 }
 
 function diffStatsWidth(adds: number, dels: number) {
diff --git a/web_src/js/components/DiffFileTree.vue b/web_src/js/components/DiffFileTree.vue
index 8676c4d37f..d00d03565f 100644
--- a/web_src/js/components/DiffFileTree.vue
+++ b/web_src/js/components/DiffFileTree.vue
@@ -1,5 +1,5 @@
 <script lang="ts" setup>
-import DiffFileTreeItem from './DiffFileTreeItem.vue';
+import DiffFileTreeItem, {type Item} from './DiffFileTreeItem.vue';
 import {loadMoreFiles} from '../features/repo-diff.ts';
 import {toggleElem} from '../utils/dom.ts';
 import {diffTreeStore} from '../modules/stores.ts';
@@ -11,7 +11,7 @@ const LOCAL_STORAGE_KEY = 'diff_file_tree_visible';
 const store = diffTreeStore();
 
 const fileTree = computed(() => {
-  const result = [];
+  const result: Array<Item> = [];
   for (const file of store.files) {
     // Split file into directories
     const splits = file.Name.split('/');
@@ -24,15 +24,10 @@ const fileTree = computed(() => {
       if (index === splits.length) {
         isFile = true;
       }
-      let newParent = {
+      let newParent: Item = {
         name: split,
         children: [],
         isFile,
-      } as {
-        name: string,
-        children: any[],
-        isFile: boolean,
-        file?: any,
       };
 
       if (isFile === true) {
diff --git a/web_src/js/components/DiffFileTreeItem.vue b/web_src/js/components/DiffFileTreeItem.vue
index 9a21a8ac10..d3be10e3e9 100644
--- a/web_src/js/components/DiffFileTreeItem.vue
+++ b/web_src/js/components/DiffFileTreeItem.vue
@@ -1,5 +1,5 @@
 <script lang="ts" setup>
-import {SvgIcon} from '../svg.ts';
+import {SvgIcon, type SvgName} from '../svg.ts';
 import {diffTreeStore} from '../modules/stores.ts';
 import {ref} from 'vue';
 
@@ -11,7 +11,7 @@ type File = {
   IsSubmodule: boolean;
 }
 
-type Item = {
+export type Item = {
   name: string;
   isFile: boolean;
   file?: File;
@@ -26,14 +26,14 @@ const store = diffTreeStore();
 const collapsed = ref(false);
 
 function getIconForDiffType(pType: number) {
-  const diffTypes = {
-    1: {name: 'octicon-diff-added', classes: ['text', 'green']},
-    2: {name: 'octicon-diff-modified', classes: ['text', 'yellow']},
-    3: {name: 'octicon-diff-removed', classes: ['text', 'red']},
-    4: {name: 'octicon-diff-renamed', classes: ['text', 'teal']},
-    5: {name: 'octicon-diff-renamed', classes: ['text', 'green']}, // there is no octicon for copied, so renamed should be ok
+  const diffTypes: Record<string, {name: SvgName, classes: Array<string>}> = {
+    '1': {name: 'octicon-diff-added', classes: ['text', 'green']},
+    '2': {name: 'octicon-diff-modified', classes: ['text', 'yellow']},
+    '3': {name: 'octicon-diff-removed', classes: ['text', 'red']},
+    '4': {name: 'octicon-diff-renamed', classes: ['text', 'teal']},
+    '5': {name: 'octicon-diff-renamed', classes: ['text', 'green']}, // there is no octicon for copied, so renamed should be ok
   };
-  return diffTypes[pType];
+  return diffTypes[String(pType)];
 }
 
 function fileIcon(file: File) {
diff --git a/web_src/js/components/PullRequestMergeForm.vue b/web_src/js/components/PullRequestMergeForm.vue
index 1393a7f258..4f291f5ca1 100644
--- a/web_src/js/components/PullRequestMergeForm.vue
+++ b/web_src/js/components/PullRequestMergeForm.vue
@@ -36,17 +36,17 @@ const forceMerge = computed(() => {
 });
 
 watch(mergeStyle, (val) => {
-  mergeStyleDetail.value = mergeForm.value.mergeStyles.find((e) => e.name === val);
+  mergeStyleDetail.value = mergeForm.value.mergeStyles.find((e: any) => e.name === val);
   for (const elem of document.querySelectorAll('[data-pull-merge-style]')) {
     toggleElem(elem, elem.getAttribute('data-pull-merge-style') === val);
   }
 });
 
 onMounted(() => {
-  mergeStyleAllowedCount.value = mergeForm.value.mergeStyles.reduce((v, msd) => v + (msd.allowed ? 1 : 0), 0);
+  mergeStyleAllowedCount.value = mergeForm.value.mergeStyles.reduce((v: any, msd: any) => v + (msd.allowed ? 1 : 0), 0);
 
-  let mergeStyle = mergeForm.value.mergeStyles.find((e) => e.allowed && e.name === mergeForm.value.defaultMergeStyle)?.name;
-  if (!mergeStyle) mergeStyle = mergeForm.value.mergeStyles.find((e) => e.allowed)?.name;
+  let mergeStyle = mergeForm.value.mergeStyles.find((e: any) => e.allowed && e.name === mergeForm.value.defaultMergeStyle)?.name;
+  if (!mergeStyle) mergeStyle = mergeForm.value.mergeStyles.find((e: any) => e.allowed)?.name;
   switchMergeStyle(mergeStyle, !mergeForm.value.canMergeNow);
 
   document.addEventListener('mouseup', hideMergeStyleMenu);
diff --git a/web_src/js/components/RepoActionView.vue b/web_src/js/components/RepoActionView.vue
index 79b43a3746..03c8464060 100644
--- a/web_src/js/components/RepoActionView.vue
+++ b/web_src/js/components/RepoActionView.vue
@@ -6,6 +6,7 @@ import {createElementFromAttrs, toggleElem} from '../utils/dom.ts';
 import {formatDatetime} from '../utils/time.ts';
 import {renderAnsi} from '../render/ansi.ts';
 import {POST, DELETE} from '../modules/fetch.ts';
+import type {IntervalId} from '../types.ts';
 
 // see "models/actions/status.go", if it needs to be used somewhere else, move it to a shared file like "types/actions.ts"
 type RunStatus = 'unknown' | 'waiting' | 'running' | 'success' | 'failure' | 'cancelled' | 'skipped' | 'blocked';
@@ -24,6 +25,20 @@ type LogLineCommand = {
   prefix: string,
 }
 
+type Job = {
+  id: number;
+  name: string;
+  status: RunStatus;
+  canRerun: boolean;
+  duration: string;
+}
+
+type Step = {
+  summary: string,
+  duration: string,
+  status: RunStatus,
+}
+
 function parseLineCommand(line: LogLine): LogLineCommand | null {
   for (const prefix of LogLinePrefixesGroup) {
     if (line.message.startsWith(prefix)) {
@@ -77,7 +92,7 @@ export default defineComponent({
       default: '',
     },
     locale: {
-      type: Object as PropType<Record<string, string>>,
+      type: Object as PropType<Record<string, any>>,
       default: null,
     },
   },
@@ -86,10 +101,10 @@ export default defineComponent({
     const {autoScroll, expandRunning} = getLocaleStorageOptions();
     return {
       // internal state
-      loadingAbortController: null,
-      intervalID: null,
-      currentJobStepsStates: [],
-      artifacts: [],
+      loadingAbortController: null as AbortController | null,
+      intervalID: null as IntervalId | null,
+      currentJobStepsStates: [] as Array<Record<string, any>>,
+      artifacts: [] as Array<Record<string, any>>,
       onHoverRerunIndex: -1,
       menuVisible: false,
       isFullScreen: false,
@@ -122,7 +137,7 @@ export default defineComponent({
           //   canRerun: false,
           //   duration: '',
           // },
-        ],
+        ] as Array<Job>,
         commit: {
           localeCommit: '',
           localePushedBy: '',
@@ -148,7 +163,7 @@ export default defineComponent({
           //   duration: '',
           //   status: '',
           // }
-        ],
+        ] as Array<Step>,
       },
     };
   },
@@ -194,7 +209,7 @@ export default defineComponent({
 
     // get the job step logs container ('.job-step-logs')
     getJobStepLogsContainer(stepIndex: number): HTMLElement {
-      return this.$refs.logs[stepIndex];
+      return (this.$refs.logs as any)[stepIndex];
     },
 
     // get the active logs container element, either the `job-step-logs` or the `job-log-list` in the `job-log-group`
@@ -205,7 +220,7 @@ export default defineComponent({
     },
     // begin a log group
     beginLogGroup(stepIndex: number, startTime: number, line: LogLine, cmd: LogLineCommand) {
-      const el = this.$refs.logs[stepIndex];
+      const el = (this.$refs.logs as any)[stepIndex];
       const elJobLogGroupSummary = createElementFromAttrs('summary', {class: 'job-log-group-summary'},
         this.createLogLine(stepIndex, startTime, {
           index: line.index,
@@ -223,7 +238,7 @@ export default defineComponent({
     },
     // end a log group
     endLogGroup(stepIndex: number, startTime: number, line: LogLine, cmd: LogLineCommand) {
-      const el = this.$refs.logs[stepIndex];
+      const el = (this.$refs.logs as any)[stepIndex];
       el._stepLogsActiveContainer = null;
       el.append(this.createLogLine(stepIndex, startTime, {
         index: line.index,
@@ -393,7 +408,7 @@ export default defineComponent({
       if (this.menuVisible) this.menuVisible = false;
     },
 
-    toggleTimeDisplay(type: string) {
+    toggleTimeDisplay(type: 'seconds' | 'stamp') {
       this.timeVisible[`log-time-${type}`] = !this.timeVisible[`log-time-${type}`];
       for (const el of (this.$refs.steps as HTMLElement).querySelectorAll(`.log-time-${type}`)) {
         toggleElem(el, this.timeVisible[`log-time-${type}`]);
@@ -422,9 +437,10 @@ export default defineComponent({
       const selectedLogStep = window.location.hash;
       if (!selectedLogStep) return;
       const [_, step, _line] = selectedLogStep.split('-');
-      if (!this.currentJobStepsStates[step]) return;
-      if (!this.currentJobStepsStates[step].expanded && this.currentJobStepsStates[step].cursor === null) {
-        this.currentJobStepsStates[step].expanded = true;
+      const stepNum = Number(step);
+      if (!this.currentJobStepsStates[stepNum]) return;
+      if (!this.currentJobStepsStates[stepNum].expanded && this.currentJobStepsStates[stepNum].cursor === null) {
+        this.currentJobStepsStates[stepNum].expanded = true;
         // need to await for load job if the step log is loaded for the first time
         // so logline can be selected by querySelector
         await this.loadJob();
diff --git a/web_src/js/components/RepoActivityTopAuthors.vue b/web_src/js/components/RepoActivityTopAuthors.vue
index 1295e15582..77b85bd7e2 100644
--- a/web_src/js/components/RepoActivityTopAuthors.vue
+++ b/web_src/js/components/RepoActivityTopAuthors.vue
@@ -1,4 +1,5 @@
 <script lang="ts" setup>
+// @ts-expect-error - module exports no types
 import {VueBarGraph} from 'vue-bar-graph';
 import {computed, onMounted, ref} from 'vue';
 
diff --git a/web_src/js/components/RepoBranchTagSelector.vue b/web_src/js/components/RepoBranchTagSelector.vue
index 7e35d55b2f..fa5c75af99 100644
--- a/web_src/js/components/RepoBranchTagSelector.vue
+++ b/web_src/js/components/RepoBranchTagSelector.vue
@@ -157,7 +157,7 @@ export default defineComponent({
       // @ts-expect-error - el is unknown type
       return (el && el.length) ? el[0] : null;
     },
-    keydown(e) {
+    keydown(e: KeyboardEvent) {
       if (e.key === 'ArrowUp' || e.key === 'ArrowDown') {
         e.preventDefault();
 
@@ -181,7 +181,7 @@ export default defineComponent({
         this.menuVisible = false;
       }
     },
-    handleTabSwitch(selectedTab) {
+    handleTabSwitch(selectedTab: SelectedTab) {
       this.selectedTab = selectedTab;
       this.focusSearchField();
       this.loadTabItems();
diff --git a/web_src/js/components/RepoContributors.vue b/web_src/js/components/RepoContributors.vue
index 5d2c74b6a9..6ad2c848b1 100644
--- a/web_src/js/components/RepoContributors.vue
+++ b/web_src/js/components/RepoContributors.vue
@@ -80,10 +80,10 @@ export default defineComponent({
     sortedContributors: {} as Record<string, any>,
     type: 'commits',
     contributorsStats: {} as Record<string, any>,
-    xAxisStart: null,
-    xAxisEnd: null,
-    xAxisMin: null,
-    xAxisMax: null,
+    xAxisStart: null as number | null,
+    xAxisEnd: null as number | null,
+    xAxisMin: null as number | null,
+    xAxisMax: null as number | null,
   }),
   mounted() {
     this.fetchGraphData();
@@ -99,7 +99,7 @@ export default defineComponent({
   },
   methods: {
     sortContributors() {
-      const contributors = this.filterContributorWeeksByDateRange();
+      const contributors: Record<string, any> = this.filterContributorWeeksByDateRange();
       const criteria = `total_${this.type}`;
       this.sortedContributors = Object.values(contributors)
         .filter((contributor) => contributor[criteria] !== 0)
@@ -158,7 +158,7 @@ export default defineComponent({
     },
 
     filterContributorWeeksByDateRange() {
-      const filteredData = {};
+      const filteredData: Record<string, any> = {};
       const data = this.contributorsStats;
       for (const key of Object.keys(data)) {
         const user = data[key];
@@ -196,7 +196,7 @@ export default defineComponent({
       // Normally, chartjs handles this automatically, but it will resize the graph when you
       // zoom, pan etc. I think resizing the graph makes it harder to compare things visually.
       const maxValue = Math.max(
-        ...this.totalStats.weeks.map((o) => o[this.type]),
+        ...this.totalStats.weeks.map((o: Record<string, any>) => o[this.type]),
       );
       const [coefficient, exp] = maxValue.toExponential().split('e').map(Number);
       if (coefficient % 1 === 0) return maxValue;
@@ -208,7 +208,7 @@ export default defineComponent({
       // for contributors' graph. If I let chartjs do this for me, it will choose different
       // maxY value for each contributors' graph which again makes it harder to compare.
       const maxValue = Math.max(
-        ...this.sortedContributors.map((c) => c.max_contribution_type),
+        ...this.sortedContributors.map((c: Record<string, any>) => c.max_contribution_type),
       );
       const [coefficient, exp] = maxValue.toExponential().split('e').map(Number);
       if (coefficient % 1 === 0) return maxValue;
@@ -232,8 +232,8 @@ export default defineComponent({
     },
 
     updateOtherCharts({chart}: {chart: Chart}, reset: boolean = false) {
-      const minVal = chart.options.scales.x.min;
-      const maxVal = chart.options.scales.x.max;
+      const minVal = Number(chart.options.scales.x.min);
+      const maxVal = Number(chart.options.scales.x.max);
       if (reset) {
         this.xAxisMin = this.xAxisStart;
         this.xAxisMax = this.xAxisEnd;
diff --git a/web_src/js/components/ScopedAccessTokenSelector.vue b/web_src/js/components/ScopedAccessTokenSelector.vue
index 63214d0bf5..9eaf824035 100644
--- a/web_src/js/components/ScopedAccessTokenSelector.vue
+++ b/web_src/js/components/ScopedAccessTokenSelector.vue
@@ -35,7 +35,7 @@ onUnmounted(() => {
   document.querySelector('#scoped-access-submit').removeEventListener('click', onClickSubmit);
 });
 
-function onClickSubmit(e) {
+function onClickSubmit(e: Event) {
   e.preventDefault();
 
   const warningEl = document.querySelector('#scoped-access-warning');
diff --git a/web_src/js/features/admin/common.ts b/web_src/js/features/admin/common.ts
index 6c725a3efe..b991749d81 100644
--- a/web_src/js/features/admin/common.ts
+++ b/web_src/js/features/admin/common.ts
@@ -90,7 +90,7 @@ export function initAdminCommon(): void {
     onOAuth2UseCustomURLChange(applyDefaultValues);
   }
 
-  function onOAuth2UseCustomURLChange(applyDefaultValues) {
+  function onOAuth2UseCustomURLChange(applyDefaultValues: boolean) {
     const provider = document.querySelector<HTMLInputElement>('#oauth2_provider').value;
     hideElem('.oauth2_use_custom_url_field');
     for (const input of document.querySelectorAll<HTMLInputElement>('.oauth2_use_custom_url_field input[required]')) {
diff --git a/web_src/js/features/citation.ts b/web_src/js/features/citation.ts
index fc5bb38f0a..3c9fe0afc8 100644
--- a/web_src/js/features/citation.ts
+++ b/web_src/js/features/citation.ts
@@ -5,9 +5,13 @@ const {pageData} = window.config;
 
 async function initInputCitationValue(citationCopyApa: HTMLButtonElement, citationCopyBibtex: HTMLButtonElement) {
   const [{Cite, plugins}] = await Promise.all([
+    // @ts-expect-error: module exports no types
     import(/* webpackChunkName: "citation-js-core" */'@citation-js/core'),
+    // @ts-expect-error: module exports no types
     import(/* webpackChunkName: "citation-js-formats" */'@citation-js/plugin-software-formats'),
+    // @ts-expect-error: module exports no types
     import(/* webpackChunkName: "citation-js-bibtex" */'@citation-js/plugin-bibtex'),
+    // @ts-expect-error: module exports no types
     import(/* webpackChunkName: "citation-js-csl" */'@citation-js/plugin-csl'),
   ]);
   const {citationFileContent} = pageData;
diff --git a/web_src/js/features/common-button.ts b/web_src/js/features/common-button.ts
index 3162557b9b..7aebdd8dd5 100644
--- a/web_src/js/features/common-button.ts
+++ b/web_src/js/features/common-button.ts
@@ -74,10 +74,10 @@ export function initGlobalDeleteButton(): void {
   }
 }
 
-function onShowPanelClick(e) {
+function onShowPanelClick(e: MouseEvent) {
   // a '.show-panel' element can show a panel, by `data-panel="selector"`
   // if it has "toggle" class, it toggles the panel
-  const el = e.currentTarget;
+  const el = e.currentTarget as HTMLElement;
   e.preventDefault();
   const sel = el.getAttribute('data-panel');
   if (el.classList.contains('toggle')) {
@@ -87,9 +87,9 @@ function onShowPanelClick(e) {
   }
 }
 
-function onHidePanelClick(e) {
+function onHidePanelClick(e: MouseEvent) {
   // a `.hide-panel` element can hide a panel, by `data-panel="selector"` or `data-panel-closest="selector"`
-  const el = e.currentTarget;
+  const el = e.currentTarget as HTMLElement;
   e.preventDefault();
   let sel = el.getAttribute('data-panel');
   if (sel) {
@@ -98,13 +98,13 @@ function onHidePanelClick(e) {
   }
   sel = el.getAttribute('data-panel-closest');
   if (sel) {
-    hideElem(el.parentNode.closest(sel));
+    hideElem((el.parentNode as HTMLElement).closest(sel));
     return;
   }
   throw new Error('no panel to hide'); // should never happen, otherwise there is a bug in code
 }
 
-function onShowModalClick(e) {
+function onShowModalClick(e: MouseEvent) {
   // A ".show-modal" button will show a modal dialog defined by its "data-modal" attribute.
   // Each "data-modal-{target}" attribute will be filled to target element's value or text-content.
   // * First, try to query '#target'
@@ -112,7 +112,7 @@ function onShowModalClick(e) {
   // * Then, try to query '.target'
   // * Then, try to query 'target' as HTML tag
   // If there is a ".{attr}" part like "data-modal-form.action", then the form's "action" attribute will be set.
-  const el = e.currentTarget;
+  const el = e.currentTarget as HTMLElement;
   e.preventDefault();
   const modalSelector = el.getAttribute('data-modal');
   const elModal = document.querySelector(modalSelector);
@@ -137,9 +137,9 @@ function onShowModalClick(e) {
     }
 
     if (attrTargetAttr) {
-      attrTarget[camelize(attrTargetAttr)] = attrib.value;
+      (attrTarget as any)[camelize(attrTargetAttr)] = attrib.value;
     } else if (attrTarget.matches('input, textarea')) {
-      attrTarget.value = attrib.value; // FIXME: add more supports like checkbox
+      (attrTarget as HTMLInputElement | HTMLTextAreaElement).value = attrib.value; // FIXME: add more supports like checkbox
     } else {
       attrTarget.textContent = attrib.value; // FIXME: it should be more strict here, only handle div/span/p
     }
diff --git a/web_src/js/features/common-fetch-action.ts b/web_src/js/features/common-fetch-action.ts
index bc72f4089a..2da481e521 100644
--- a/web_src/js/features/common-fetch-action.ts
+++ b/web_src/js/features/common-fetch-action.ts
@@ -75,7 +75,10 @@ async function formFetchAction(formEl: HTMLFormElement, e: SubmitEvent) {
   }
 
   let reqUrl = formActionUrl;
-  const reqOpt = {method: formMethod.toUpperCase(), body: null};
+  const reqOpt = {
+    method: formMethod.toUpperCase(),
+    body: null as FormData | null,
+  };
   if (formMethod.toLowerCase() === 'get') {
     const params = new URLSearchParams();
     for (const [key, value] of formData) {
diff --git a/web_src/js/features/common-form.ts b/web_src/js/features/common-form.ts
index 8532d397cd..7321d80c44 100644
--- a/web_src/js/features/common-form.ts
+++ b/web_src/js/features/common-form.ts
@@ -17,13 +17,13 @@ export function initGlobalEnterQuickSubmit() {
     if (e.key !== 'Enter') return;
     const hasCtrlOrMeta = ((e.ctrlKey || e.metaKey) && !e.altKey);
     if (hasCtrlOrMeta && e.target.matches('textarea')) {
-      if (handleGlobalEnterQuickSubmit(e.target)) {
+      if (handleGlobalEnterQuickSubmit(e.target as HTMLElement)) {
         e.preventDefault();
       }
     } else if (e.target.matches('input') && !e.target.closest('form')) {
       // input in a normal form could handle Enter key by default, so we only handle the input outside a form
       // eslint-disable-next-line unicorn/no-lonely-if
-      if (handleGlobalEnterQuickSubmit(e.target)) {
+      if (handleGlobalEnterQuickSubmit(e.target as HTMLElement)) {
         e.preventDefault();
       }
     }
diff --git a/web_src/js/features/comp/ComboMarkdownEditor.ts b/web_src/js/features/comp/ComboMarkdownEditor.ts
index bba50a1296..d3773a89c4 100644
--- a/web_src/js/features/comp/ComboMarkdownEditor.ts
+++ b/web_src/js/features/comp/ComboMarkdownEditor.ts
@@ -29,10 +29,10 @@ let elementIdCounter = 0;
 
 /**
  * validate if the given textarea is non-empty.
- * @param {HTMLElement} textarea - The textarea element to be validated.
+ * @param {HTMLTextAreaElement} textarea - The textarea element to be validated.
  * @returns {boolean} returns true if validation succeeded.
  */
-export function validateTextareaNonEmpty(textarea) {
+export function validateTextareaNonEmpty(textarea: HTMLTextAreaElement) {
   // When using EasyMDE, the original edit area HTML element is hidden, breaking HTML5 input validation.
   // The workaround (https://github.com/sparksuite/simplemde-markdown-editor/issues/324) doesn't work with contenteditable, so we just show an alert.
   if (!textarea.value) {
@@ -49,16 +49,25 @@ export function validateTextareaNonEmpty(textarea) {
   return true;
 }
 
+type Heights = {
+  minHeight?: string,
+  height?: string,
+  maxHeight?: string,
+};
+
 type ComboMarkdownEditorOptions = {
-  editorHeights?: {minHeight?: string, height?: string, maxHeight?: string},
+  editorHeights?: Heights,
   easyMDEOptions?: EasyMDE.Options,
 };
 
+type ComboMarkdownEditorTextarea = HTMLTextAreaElement & {_giteaComboMarkdownEditor: any};
+type ComboMarkdownEditorContainer = HTMLElement & {_giteaComboMarkdownEditor?: any};
+
 export class ComboMarkdownEditor {
   static EventEditorContentChanged = EventEditorContentChanged;
   static EventUploadStateChanged = EventUploadStateChanged;
 
-  public container : HTMLElement;
+  public container: HTMLElement;
 
   options: ComboMarkdownEditorOptions;
 
@@ -70,7 +79,7 @@ export class ComboMarkdownEditor {
   easyMDEToolbarActions: any;
   easyMDEToolbarDefault: any;
 
-  textarea: HTMLTextAreaElement & {_giteaComboMarkdownEditor: any};
+  textarea: ComboMarkdownEditorTextarea;
   textareaMarkdownToolbar: HTMLElement;
   textareaAutosize: any;
 
@@ -81,7 +90,7 @@ export class ComboMarkdownEditor {
   previewUrl: string;
   previewContext: string;
 
-  constructor(container, options:ComboMarkdownEditorOptions = {}) {
+  constructor(container: ComboMarkdownEditorContainer, options:ComboMarkdownEditorOptions = {}) {
     if (container._giteaComboMarkdownEditor) throw new Error('ComboMarkdownEditor already initialized');
     container._giteaComboMarkdownEditor = this;
     this.options = options;
@@ -98,7 +107,7 @@ export class ComboMarkdownEditor {
     await this.switchToUserPreference();
   }
 
-  applyEditorHeights(el, heights) {
+  applyEditorHeights(el: HTMLElement, heights: Heights) {
     if (!heights) return;
     if (heights.minHeight) el.style.minHeight = heights.minHeight;
     if (heights.height) el.style.height = heights.height;
@@ -283,7 +292,7 @@ export class ComboMarkdownEditor {
     ];
   }
 
-  parseEasyMDEToolbar(easyMde: typeof EasyMDE, actions) {
+  parseEasyMDEToolbar(easyMde: typeof EasyMDE, actions: any) {
     this.easyMDEToolbarActions = this.easyMDEToolbarActions || easyMDEToolbarActions(easyMde, this);
     const processed = [];
     for (const action of actions) {
@@ -332,21 +341,21 @@ export class ComboMarkdownEditor {
     this.easyMDE = new EasyMDE(easyMDEOpt);
     this.easyMDE.codemirror.on('change', () => triggerEditorContentChanged(this.container));
     this.easyMDE.codemirror.setOption('extraKeys', {
-      'Cmd-Enter': (cm) => handleGlobalEnterQuickSubmit(cm.getTextArea()),
-      'Ctrl-Enter': (cm) => handleGlobalEnterQuickSubmit(cm.getTextArea()),
-      Enter: (cm) => {
+      'Cmd-Enter': (cm: any) => handleGlobalEnterQuickSubmit(cm.getTextArea()),
+      'Ctrl-Enter': (cm: any) => handleGlobalEnterQuickSubmit(cm.getTextArea()),
+      Enter: (cm: any) => {
         const tributeContainer = document.querySelector<HTMLElement>('.tribute-container');
         if (!tributeContainer || tributeContainer.style.display === 'none') {
           cm.execCommand('newlineAndIndent');
         }
       },
-      Up: (cm) => {
+      Up: (cm: any) => {
         const tributeContainer = document.querySelector<HTMLElement>('.tribute-container');
         if (!tributeContainer || tributeContainer.style.display === 'none') {
           return cm.execCommand('goLineUp');
         }
       },
-      Down: (cm) => {
+      Down: (cm: any) => {
         const tributeContainer = document.querySelector<HTMLElement>('.tribute-container');
         if (!tributeContainer || tributeContainer.style.display === 'none') {
           return cm.execCommand('goLineDown');
@@ -354,14 +363,14 @@ export class ComboMarkdownEditor {
       },
     });
     this.applyEditorHeights(this.container.querySelector('.CodeMirror-scroll'), this.options.editorHeights);
-    await attachTribute(this.easyMDE.codemirror.getInputField(), {mentions: true, emoji: true});
+    await attachTribute(this.easyMDE.codemirror.getInputField());
     if (this.dropzone) {
       initEasyMDEPaste(this.easyMDE, this.dropzone);
     }
     hideElem(this.textareaMarkdownToolbar);
   }
 
-  value(v = undefined) {
+  value(v: any = undefined) {
     if (v === undefined) {
       if (this.easyMDE) {
         return this.easyMDE.value();
@@ -402,7 +411,7 @@ export class ComboMarkdownEditor {
   }
 }
 
-export function getComboMarkdownEditor(el) {
+export function getComboMarkdownEditor(el: any) {
   if (!el) return null;
   if (el.length) el = el[0];
   return el._giteaComboMarkdownEditor;
diff --git a/web_src/js/features/comp/EditorMarkdown.ts b/web_src/js/features/comp/EditorMarkdown.ts
index 08306531f1..6e66c15763 100644
--- a/web_src/js/features/comp/EditorMarkdown.ts
+++ b/web_src/js/features/comp/EditorMarkdown.ts
@@ -1,10 +1,10 @@
 export const EventEditorContentChanged = 'ce-editor-content-changed';
 
-export function triggerEditorContentChanged(target) {
+export function triggerEditorContentChanged(target: HTMLElement) {
   target.dispatchEvent(new CustomEvent(EventEditorContentChanged, {bubbles: true}));
 }
 
-export function textareaInsertText(textarea, value) {
+export function textareaInsertText(textarea: HTMLTextAreaElement, value: string) {
   const startPos = textarea.selectionStart;
   const endPos = textarea.selectionEnd;
   textarea.value = textarea.value.substring(0, startPos) + value + textarea.value.substring(endPos);
@@ -20,7 +20,7 @@ type TextareaValueSelection = {
   selEnd: number;
 }
 
-function handleIndentSelection(textarea: HTMLTextAreaElement, e) {
+function handleIndentSelection(textarea: HTMLTextAreaElement, e: KeyboardEvent) {
   const selStart = textarea.selectionStart;
   const selEnd = textarea.selectionEnd;
   if (selEnd === selStart) return; // do not process when no selection
@@ -188,7 +188,7 @@ function isTextExpanderShown(textarea: HTMLElement): boolean {
   return Boolean(textarea.closest('text-expander')?.querySelector('.suggestions'));
 }
 
-export function initTextareaMarkdown(textarea) {
+export function initTextareaMarkdown(textarea: HTMLTextAreaElement) {
   textarea.addEventListener('keydown', (e) => {
     if (isTextExpanderShown(textarea)) return;
     if (e.key === 'Tab' && !e.ctrlKey && !e.metaKey && !e.altKey) {
diff --git a/web_src/js/features/comp/EditorUpload.ts b/web_src/js/features/comp/EditorUpload.ts
index 89982747ea..f6d5731422 100644
--- a/web_src/js/features/comp/EditorUpload.ts
+++ b/web_src/js/features/comp/EditorUpload.ts
@@ -8,43 +8,46 @@ import {
   generateMarkdownLinkForAttachment,
 } from '../dropzone.ts';
 import type CodeMirror from 'codemirror';
+import type EasyMDE from 'easymde';
+import type {DropzoneFile} from 'dropzone';
 
 let uploadIdCounter = 0;
 
 export const EventUploadStateChanged = 'ce-upload-state-changed';
 
-export function triggerUploadStateChanged(target) {
+export function triggerUploadStateChanged(target: HTMLElement) {
   target.dispatchEvent(new CustomEvent(EventUploadStateChanged, {bubbles: true}));
 }
 
-function uploadFile(dropzoneEl, file) {
+function uploadFile(dropzoneEl: HTMLElement, file: File) {
   return new Promise((resolve) => {
     const curUploadId = uploadIdCounter++;
-    file._giteaUploadId = curUploadId;
+    (file as any)._giteaUploadId = curUploadId;
     const dropzoneInst = dropzoneEl.dropzone;
-    const onUploadDone = ({file}) => {
+    const onUploadDone = ({file}: {file: any}) => {
       if (file._giteaUploadId === curUploadId) {
         dropzoneInst.off(DropzoneCustomEventUploadDone, onUploadDone);
         resolve(file);
       }
     };
     dropzoneInst.on(DropzoneCustomEventUploadDone, onUploadDone);
-    dropzoneInst.handleFiles([file]);
+    // FIXME: this is not entirely correct because `file` does not satisfy DropzoneFile (we have abused the Dropzone for long time)
+    dropzoneInst.addFile(file as DropzoneFile);
   });
 }
 
 class TextareaEditor {
-  editor : HTMLTextAreaElement;
+  editor: HTMLTextAreaElement;
 
-  constructor(editor) {
+  constructor(editor: HTMLTextAreaElement) {
     this.editor = editor;
   }
 
-  insertPlaceholder(value) {
+  insertPlaceholder(value: string) {
     textareaInsertText(this.editor, value);
   }
 
-  replacePlaceholder(oldVal, newVal) {
+  replacePlaceholder(oldVal: string, newVal: string) {
     const editor = this.editor;
     const startPos = editor.selectionStart;
     const endPos = editor.selectionEnd;
@@ -65,11 +68,11 @@ class TextareaEditor {
 class CodeMirrorEditor {
   editor: CodeMirror.EditorFromTextArea;
 
-  constructor(editor) {
+  constructor(editor: CodeMirror.EditorFromTextArea) {
     this.editor = editor;
   }
 
-  insertPlaceholder(value) {
+  insertPlaceholder(value: string) {
     const editor = this.editor;
     const startPoint = editor.getCursor('start');
     const endPoint = editor.getCursor('end');
@@ -80,7 +83,7 @@ class CodeMirrorEditor {
     triggerEditorContentChanged(editor.getTextArea());
   }
 
-  replacePlaceholder(oldVal, newVal) {
+  replacePlaceholder(oldVal: string, newVal: string) {
     const editor = this.editor;
     const endPoint = editor.getCursor('end');
     if (editor.getSelection() === oldVal) {
@@ -96,7 +99,7 @@ class CodeMirrorEditor {
   }
 }
 
-async function handleUploadFiles(editor, dropzoneEl, files, e) {
+async function handleUploadFiles(editor: CodeMirrorEditor | TextareaEditor, dropzoneEl: HTMLElement, files: Array<File> | FileList, e: Event) {
   e.preventDefault();
   for (const file of files) {
     const name = file.name.slice(0, file.name.lastIndexOf('.'));
@@ -109,13 +112,13 @@ async function handleUploadFiles(editor, dropzoneEl, files, e) {
   }
 }
 
-export function removeAttachmentLinksFromMarkdown(text, fileUuid) {
+export function removeAttachmentLinksFromMarkdown(text: string, fileUuid: string) {
   text = text.replace(new RegExp(`!?\\[([^\\]]+)\\]\\(/?attachments/${fileUuid}\\)`, 'g'), '');
   text = text.replace(new RegExp(`<img[^>]+src="/?attachments/${fileUuid}"[^>]*>`, 'g'), '');
   return text;
 }
 
-function handleClipboardText(textarea, e, {text, isShiftDown}) {
+function handleClipboardText(textarea: HTMLTextAreaElement, e: ClipboardEvent, text: string, isShiftDown: boolean) {
   // pasting with "shift" means "paste as original content" in most applications
   if (isShiftDown) return; // let the browser handle it
 
@@ -131,7 +134,7 @@ function handleClipboardText(textarea, e, {text, isShiftDown}) {
 }
 
 // extract text and images from "paste" event
-function getPastedContent(e) {
+function getPastedContent(e: ClipboardEvent) {
   const images = [];
   for (const item of e.clipboardData?.items ?? []) {
     if (item.type?.startsWith('image/')) {
@@ -142,8 +145,8 @@ function getPastedContent(e) {
   return {text, images};
 }
 
-export function initEasyMDEPaste(easyMDE, dropzoneEl) {
-  const editor = new CodeMirrorEditor(easyMDE.codemirror);
+export function initEasyMDEPaste(easyMDE: EasyMDE, dropzoneEl: HTMLElement) {
+  const editor = new CodeMirrorEditor(easyMDE.codemirror as any);
   easyMDE.codemirror.on('paste', (_, e) => {
     const {images} = getPastedContent(e);
     if (!images.length) return;
@@ -160,28 +163,28 @@ export function initEasyMDEPaste(easyMDE, dropzoneEl) {
   });
 }
 
-export function initTextareaEvents(textarea, dropzoneEl) {
+export function initTextareaEvents(textarea: HTMLTextAreaElement, dropzoneEl: HTMLElement) {
   let isShiftDown = false;
-  textarea.addEventListener('keydown', (e) => {
+  textarea.addEventListener('keydown', (e: KeyboardEvent) => {
     if (e.shiftKey) isShiftDown = true;
   });
-  textarea.addEventListener('keyup', (e) => {
+  textarea.addEventListener('keyup', (e: KeyboardEvent) => {
     if (!e.shiftKey) isShiftDown = false;
   });
-  textarea.addEventListener('paste', (e) => {
+  textarea.addEventListener('paste', (e: ClipboardEvent) => {
     const {images, text} = getPastedContent(e);
     if (images.length && dropzoneEl) {
       handleUploadFiles(new TextareaEditor(textarea), dropzoneEl, images, e);
     } else if (text) {
-      handleClipboardText(textarea, e, {text, isShiftDown});
+      handleClipboardText(textarea, e, text, isShiftDown);
     }
   });
-  textarea.addEventListener('drop', (e) => {
+  textarea.addEventListener('drop', (e: DragEvent) => {
     if (!e.dataTransfer.files.length) return;
     if (!dropzoneEl) return;
     handleUploadFiles(new TextareaEditor(textarea), dropzoneEl, e.dataTransfer.files, e);
   });
-  dropzoneEl?.dropzone.on(DropzoneCustomEventRemovedFile, ({fileUuid}) => {
+  dropzoneEl?.dropzone.on(DropzoneCustomEventRemovedFile, ({fileUuid}: {fileUuid: string}) => {
     const newText = removeAttachmentLinksFromMarkdown(textarea.value, fileUuid);
     if (textarea.value !== newText) textarea.value = newText;
   });
diff --git a/web_src/js/features/comp/QuickSubmit.ts b/web_src/js/features/comp/QuickSubmit.ts
index 385acb319f..0a41f69132 100644
--- a/web_src/js/features/comp/QuickSubmit.ts
+++ b/web_src/js/features/comp/QuickSubmit.ts
@@ -1,6 +1,6 @@
 import {querySingleVisibleElem} from '../../utils/dom.ts';
 
-export function handleGlobalEnterQuickSubmit(target) {
+export function handleGlobalEnterQuickSubmit(target: HTMLElement) {
   let form = target.closest('form');
   if (form) {
     if (!form.checkValidity()) {
diff --git a/web_src/js/features/comp/SearchUserBox.ts b/web_src/js/features/comp/SearchUserBox.ts
index 2e3b3f83be..9fedb3ed24 100644
--- a/web_src/js/features/comp/SearchUserBox.ts
+++ b/web_src/js/features/comp/SearchUserBox.ts
@@ -14,7 +14,7 @@ export function initCompSearchUserBox() {
     minCharacters: 2,
     apiSettings: {
       url: `${appSubUrl}/user/search_candidates?q={query}`,
-      onResponse(response) {
+      onResponse(response: any) {
         const resultItems = [];
         const searchQuery = searchUserBox.querySelector('input').value;
         const searchQueryUppercase = searchQuery.toUpperCase();
diff --git a/web_src/js/features/comp/TextExpander.ts b/web_src/js/features/comp/TextExpander.ts
index bad8d2e59d..dc08d1739d 100644
--- a/web_src/js/features/comp/TextExpander.ts
+++ b/web_src/js/features/comp/TextExpander.ts
@@ -5,6 +5,7 @@ import {parseIssueHref, parseRepoOwnerPathInfo} from '../../utils.ts';
 import {createElementFromAttrs, createElementFromHTML} from '../../utils/dom.ts';
 import {getIssueColor, getIssueIcon} from '../issue.ts';
 import {debounce} from 'perfect-debounce';
+import type TextExpanderElement from '@github/text-expander-element';
 
 const debouncedSuggestIssues = debounce((key: string, text: string) => new Promise<{matched:boolean; fragment?: HTMLElement}>(async (resolve) => {
   const issuePathInfo = parseIssueHref(window.location.href);
@@ -32,8 +33,8 @@ const debouncedSuggestIssues = debounce((key: string, text: string) => new Promi
   resolve({matched: true, fragment: ul});
 }), 100);
 
-export function initTextExpander(expander) {
-  expander?.addEventListener('text-expander-change', ({detail: {key, provide, text}}) => {
+export function initTextExpander(expander: TextExpanderElement) {
+  expander?.addEventListener('text-expander-change', ({detail: {key, provide, text}}: Record<string, any>) => {
     if (key === ':') {
       const matches = matchEmoji(text);
       if (!matches.length) return provide({matched: false});
@@ -84,7 +85,7 @@ export function initTextExpander(expander) {
       provide(debouncedSuggestIssues(key, text));
     }
   });
-  expander?.addEventListener('text-expander-value', ({detail}) => {
+  expander?.addEventListener('text-expander-value', ({detail}: Record<string, any>) => {
     if (detail?.item) {
       // add a space after @mentions and #issue as it's likely the user wants one
       const suffix = ['@', '#'].includes(detail.key) ? ' ' : '';
diff --git a/web_src/js/features/contextpopup.ts b/web_src/js/features/contextpopup.ts
index 33eead8431..7477331dbe 100644
--- a/web_src/js/features/contextpopup.ts
+++ b/web_src/js/features/contextpopup.ts
@@ -4,11 +4,11 @@ import {parseIssueHref} from '../utils.ts';
 import {createTippy} from '../modules/tippy.ts';
 
 export function initContextPopups() {
-  const refIssues = document.querySelectorAll('.ref-issue');
+  const refIssues = document.querySelectorAll<HTMLElement>('.ref-issue');
   attachRefIssueContextPopup(refIssues);
 }
 
-export function attachRefIssueContextPopup(refIssues) {
+export function attachRefIssueContextPopup(refIssues: NodeListOf<HTMLElement>) {
   for (const refIssue of refIssues) {
     if (refIssue.classList.contains('ref-external-issue')) continue;
 
diff --git a/web_src/js/features/copycontent.ts b/web_src/js/features/copycontent.ts
index af867463b2..4bc9281a35 100644
--- a/web_src/js/features/copycontent.ts
+++ b/web_src/js/features/copycontent.ts
@@ -46,7 +46,7 @@ export function initCopyContent() {
       showTemporaryTooltip(btn, i18n.copy_success);
     } else {
       if (isRasterImage) {
-        const success = await clippie(await convertImage(content, 'image/png'));
+        const success = await clippie(await convertImage(content as Blob, 'image/png'));
         showTemporaryTooltip(btn, success ? i18n.copy_success : i18n.copy_error);
       } else {
         showTemporaryTooltip(btn, i18n.copy_error);
diff --git a/web_src/js/features/dropzone.ts b/web_src/js/features/dropzone.ts
index 666c645230..b2ba7651c4 100644
--- a/web_src/js/features/dropzone.ts
+++ b/web_src/js/features/dropzone.ts
@@ -6,16 +6,18 @@ import {GET, POST} from '../modules/fetch.ts';
 import {showErrorToast} from '../modules/toast.ts';
 import {createElementFromHTML, createElementFromAttrs} from '../utils/dom.ts';
 import {isImageFile, isVideoFile} from '../utils.ts';
-import type {DropzoneFile} from 'dropzone/index.js';
+import type {DropzoneFile, DropzoneOptions} from 'dropzone/index.js';
 
 const {csrfToken, i18n} = window.config;
 
+type CustomDropzoneFile = DropzoneFile & {uuid: string};
+
 // dropzone has its owner event dispatcher (emitter)
 export const DropzoneCustomEventReloadFiles = 'dropzone-custom-reload-files';
 export const DropzoneCustomEventRemovedFile = 'dropzone-custom-removed-file';
 export const DropzoneCustomEventUploadDone = 'dropzone-custom-upload-done';
 
-async function createDropzone(el, opts) {
+async function createDropzone(el: HTMLElement, opts: DropzoneOptions) {
   const [{default: Dropzone}] = await Promise.all([
     import(/* webpackChunkName: "dropzone" */'dropzone'),
     import(/* webpackChunkName: "dropzone" */'dropzone/dist/dropzone.css'),
@@ -23,7 +25,7 @@ async function createDropzone(el, opts) {
   return new Dropzone(el, opts);
 }
 
-export function generateMarkdownLinkForAttachment(file, {width, dppx}: {width?: number, dppx?: number} = {}) {
+export function generateMarkdownLinkForAttachment(file: Partial<CustomDropzoneFile>, {width, dppx}: {width?: number, dppx?: number} = {}) {
   let fileMarkdown = `[${file.name}](/attachments/${file.uuid})`;
   if (isImageFile(file)) {
     fileMarkdown = `!${fileMarkdown}`;
@@ -43,7 +45,7 @@ export function generateMarkdownLinkForAttachment(file, {width, dppx}: {width?:
   return fileMarkdown;
 }
 
-function addCopyLink(file) {
+function addCopyLink(file: Partial<CustomDropzoneFile>) {
   // Create a "Copy Link" element, to conveniently copy the image or file link as Markdown to the clipboard
   // The "<a>" element has a hardcoded cursor: pointer because the default is overridden by .dropzone
   const copyLinkEl = createElementFromHTML(`
@@ -58,6 +60,8 @@ function addCopyLink(file) {
   file.previewTemplate.append(copyLinkEl);
 }
 
+type FileUuidDict = Record<string, {submitted: boolean}>;
+
 /**
  * @param {HTMLElement} dropzoneEl
  */
@@ -67,7 +71,7 @@ export async function initDropzone(dropzoneEl: HTMLElement) {
   const attachmentBaseLinkUrl = dropzoneEl.getAttribute('data-link-url');
 
   let disableRemovedfileEvent = false; // when resetting the dropzone (removeAllFiles), disable the "removedfile" event
-  let fileUuidDict = {}; // to record: if a comment has been saved, then the uploaded files won't be deleted from server when clicking the Remove in the dropzone
+  let fileUuidDict: FileUuidDict = {}; // to record: if a comment has been saved, then the uploaded files won't be deleted from server when clicking the Remove in the dropzone
   const opts: Record<string, any> = {
     url: dropzoneEl.getAttribute('data-upload-url'),
     headers: {'X-Csrf-Token': csrfToken},
@@ -89,7 +93,7 @@ export async function initDropzone(dropzoneEl: HTMLElement) {
   // "http://localhost:3000/owner/repo/issues/[object%20Event]"
   // the reason is that the preview "callback(dataURL)" is assign to "img.onerror" then "thumbnail" uses the error object as the dataURL and generates '<img src="[object Event]">'
   const dzInst = await createDropzone(dropzoneEl, opts);
-  dzInst.on('success', (file: DropzoneFile & {uuid: string}, resp: any) => {
+  dzInst.on('success', (file: CustomDropzoneFile, resp: any) => {
     file.uuid = resp.uuid;
     fileUuidDict[file.uuid] = {submitted: false};
     const input = createElementFromAttrs('input', {name: 'files', type: 'hidden', id: `dropzone-file-${resp.uuid}`, value: resp.uuid});
@@ -98,7 +102,7 @@ export async function initDropzone(dropzoneEl: HTMLElement) {
     dzInst.emit(DropzoneCustomEventUploadDone, {file});
   });
 
-  dzInst.on('removedfile', async (file: DropzoneFile & {uuid: string}) => {
+  dzInst.on('removedfile', async (file: CustomDropzoneFile) => {
     if (disableRemovedfileEvent) return;
 
     dzInst.emit(DropzoneCustomEventRemovedFile, {fileUuid: file.uuid});
diff --git a/web_src/js/features/emoji.ts b/web_src/js/features/emoji.ts
index 933aa951c5..135620e51e 100644
--- a/web_src/js/features/emoji.ts
+++ b/web_src/js/features/emoji.ts
@@ -15,13 +15,13 @@ export const emojiKeys = Object.keys(tempMap).sort((a, b) => {
   return a.localeCompare(b);
 });
 
-const emojiMap = {};
+const emojiMap: Record<string, string> = {};
 for (const key of emojiKeys) {
   emojiMap[key] = tempMap[key];
 }
 
 // retrieve HTML for given emoji name
-export function emojiHTML(name) {
+export function emojiHTML(name: string) {
   let inner;
   if (Object.hasOwn(customEmojis, name)) {
     inner = `<img alt=":${name}:" src="${assetUrlPrefix}/img/emoji/${name}.png">`;
@@ -33,6 +33,6 @@ export function emojiHTML(name) {
 }
 
 // retrieve string for given emoji name
-export function emojiString(name) {
+export function emojiString(name: string) {
   return emojiMap[name] || `:${name}:`;
 }
diff --git a/web_src/js/features/file-fold.ts b/web_src/js/features/file-fold.ts
index 6fe068341a..19950d9b9f 100644
--- a/web_src/js/features/file-fold.ts
+++ b/web_src/js/features/file-fold.ts
@@ -5,15 +5,15 @@ import {svg} from '../svg.ts';
 // The fold arrow is the icon displayed on the upper left of the file box, especially intended for components having the 'fold-file' class.
 // The file content box is the box that should be hidden or shown, especially intended for components having the 'file-content' class.
 //
-export function setFileFolding(fileContentBox, foldArrow, newFold) {
+export function setFileFolding(fileContentBox: HTMLElement, foldArrow: HTMLElement, newFold: boolean) {
   foldArrow.innerHTML = svg(`octicon-chevron-${newFold ? 'right' : 'down'}`, 18);
-  fileContentBox.setAttribute('data-folded', newFold);
+  fileContentBox.setAttribute('data-folded', String(newFold));
   if (newFold && fileContentBox.getBoundingClientRect().top < 0) {
     fileContentBox.scrollIntoView();
   }
 }
 
 // Like `setFileFolding`, except that it automatically inverts the current file folding state.
-export function invertFileFolding(fileContentBox, foldArrow) {
+export function invertFileFolding(fileContentBox:HTMLElement, foldArrow: HTMLElement) {
   setFileFolding(fileContentBox, foldArrow, fileContentBox.getAttribute('data-folded') !== 'true');
 }
diff --git a/web_src/js/features/heatmap.ts b/web_src/js/features/heatmap.ts
index 53eebc93e5..7cec82108b 100644
--- a/web_src/js/features/heatmap.ts
+++ b/web_src/js/features/heatmap.ts
@@ -7,7 +7,7 @@ export function initHeatmap() {
   if (!el) return;
 
   try {
-    const heatmap = {};
+    const heatmap: Record<string, number> = {};
     for (const {contributions, timestamp} of JSON.parse(el.getAttribute('data-heatmap-data'))) {
       // Convert to user timezone and sum contributions by date
       const dateStr = new Date(timestamp * 1000).toDateString();
diff --git a/web_src/js/features/imagediff.ts b/web_src/js/features/imagediff.ts
index cd61888f83..e62734293a 100644
--- a/web_src/js/features/imagediff.ts
+++ b/web_src/js/features/imagediff.ts
@@ -3,7 +3,7 @@ import {hideElem, loadElem, queryElemChildren, queryElems} from '../utils/dom.ts
 import {parseDom} from '../utils.ts';
 import {fomanticQuery} from '../modules/fomantic/base.ts';
 
-function getDefaultSvgBoundsIfUndefined(text, src) {
+function getDefaultSvgBoundsIfUndefined(text: string, src: string) {
   const defaultSize = 300;
   const maxSize = 99999;
 
@@ -38,7 +38,7 @@ function getDefaultSvgBoundsIfUndefined(text, src) {
   return null;
 }
 
-function createContext(imageAfter, imageBefore) {
+function createContext(imageAfter: HTMLImageElement, imageBefore: HTMLImageElement) {
   const sizeAfter = {
     width: imageAfter?.width || 0,
     height: imageAfter?.height || 0,
@@ -123,7 +123,7 @@ class ImageDiff {
     queryElemChildren(containerEl, '.image-diff-tabs', (el) => el.classList.remove('is-loading'));
   }
 
-  initSideBySide(sizes) {
+  initSideBySide(sizes: Record<string, any>) {
     let factor = 1;
     if (sizes.maxSize.width > (this.diffContainerWidth - 24) / 2) {
       factor = (this.diffContainerWidth - 24) / 2 / sizes.maxSize.width;
@@ -176,7 +176,7 @@ class ImageDiff {
     }
   }
 
-  initSwipe(sizes) {
+  initSwipe(sizes: Record<string, any>) {
     let factor = 1;
     if (sizes.maxSize.width > this.diffContainerWidth - 12) {
       factor = (this.diffContainerWidth - 12) / sizes.maxSize.width;
@@ -215,14 +215,14 @@ class ImageDiff {
 
     this.containerEl.querySelector('.swipe-bar').addEventListener('mousedown', (e) => {
       e.preventDefault();
-      this.initSwipeEventListeners(e.currentTarget);
+      this.initSwipeEventListeners(e.currentTarget as HTMLElement);
     });
   }
 
-  initSwipeEventListeners(swipeBar) {
-    const swipeFrame = swipeBar.parentNode;
+  initSwipeEventListeners(swipeBar: HTMLElement) {
+    const swipeFrame = swipeBar.parentNode as HTMLElement;
     const width = swipeFrame.clientWidth;
-    const onSwipeMouseMove = (e) => {
+    const onSwipeMouseMove = (e: MouseEvent) => {
       e.preventDefault();
       const rect = swipeFrame.getBoundingClientRect();
       const value = Math.max(0, Math.min(e.clientX - rect.left, width));
@@ -237,7 +237,7 @@ class ImageDiff {
     document.addEventListener('mouseup', removeEventListeners);
   }
 
-  initOverlay(sizes) {
+  initOverlay(sizes: Record<string, any>) {
     let factor = 1;
     if (sizes.maxSize.width > this.diffContainerWidth - 12) {
       factor = (this.diffContainerWidth - 12) / sizes.maxSize.width;
diff --git a/web_src/js/features/install.ts b/web_src/js/features/install.ts
index dddeb1e954..34df4757f9 100644
--- a/web_src/js/features/install.ts
+++ b/web_src/js/features/install.ts
@@ -12,11 +12,12 @@ export function initInstall() {
     initPreInstall();
   }
 }
+
 function initPreInstall() {
   const defaultDbUser = 'gitea';
   const defaultDbName = 'gitea';
 
-  const defaultDbHosts = {
+  const defaultDbHosts: Record<string, string> = {
     mysql: '127.0.0.1:3306',
     postgres: '127.0.0.1:5432',
     mssql: '127.0.0.1:1433',
diff --git a/web_src/js/features/org-team.ts b/web_src/js/features/org-team.ts
index e160f07bf2..d07818b0ac 100644
--- a/web_src/js/features/org-team.ts
+++ b/web_src/js/features/org-team.ts
@@ -21,7 +21,7 @@ function initOrgTeamSearchRepoBox() {
     minCharacters: 2,
     apiSettings: {
       url: `${appSubUrl}/repo/search?q={query}&uid=${$searchRepoBox.data('uid')}`,
-      onResponse(response) {
+      onResponse(response: any) {
         const items = [];
         for (const item of response.data) {
           items.push({
diff --git a/web_src/js/features/pull-view-file.ts b/web_src/js/features/pull-view-file.ts
index 5202d84b28..16ccf00084 100644
--- a/web_src/js/features/pull-view-file.ts
+++ b/web_src/js/features/pull-view-file.ts
@@ -59,13 +59,13 @@ export function initViewedCheckboxListenerFor() {
       const fileName = checkbox.getAttribute('name');
 
       // check if the file is in our difftreestore and if we find it -> change the IsViewed status
-      const fileInPageData = diffTreeStore().files.find((x) => x.Name === fileName);
+      const fileInPageData = diffTreeStore().files.find((x: Record<string, any>) => x.Name === fileName);
       if (fileInPageData) {
         fileInPageData.IsViewed = this.checked;
       }
 
       // Unfortunately, actual forms cause too many problems, hence another approach is needed
-      const files = {};
+      const files: Record<string, boolean> = {};
       files[fileName] = this.checked;
       const data: Record<string, any> = {files};
       const headCommitSHA = form.getAttribute('data-headcommit');
@@ -82,13 +82,13 @@ export function initViewedCheckboxListenerFor() {
 export function initExpandAndCollapseFilesButton() {
   // expand btn
   document.querySelector(expandFilesBtnSelector)?.addEventListener('click', () => {
-    for (const box of document.querySelectorAll('.file-content[data-folded="true"]')) {
+    for (const box of document.querySelectorAll<HTMLElement>('.file-content[data-folded="true"]')) {
       setFileFolding(box, box.querySelector('.fold-file'), false);
     }
   });
   // collapse btn, need to exclude the div of “show more”
   document.querySelector(collapseFilesBtnSelector)?.addEventListener('click', () => {
-    for (const box of document.querySelectorAll('.file-content:not([data-folded="true"])')) {
+    for (const box of document.querySelectorAll<HTMLElement>('.file-content:not([data-folded="true"])')) {
       if (box.getAttribute('id') === 'diff-incomplete') continue;
       setFileFolding(box, box.querySelector('.fold-file'), true);
     }
diff --git a/web_src/js/features/repo-common.ts b/web_src/js/features/repo-common.ts
index 90860720e4..fb76d8ed36 100644
--- a/web_src/js/features/repo-common.ts
+++ b/web_src/js/features/repo-common.ts
@@ -1,4 +1,4 @@
-import {queryElems} from '../utils/dom.ts';
+import {queryElems, type DOMEvent} from '../utils/dom.ts';
 import {POST} from '../modules/fetch.ts';
 import {showErrorToast} from '../modules/toast.ts';
 import {sleep} from '../utils.ts';
@@ -7,10 +7,10 @@ import {createApp} from 'vue';
 import {toOriginUrl} from '../utils/url.ts';
 import {createTippy} from '../modules/tippy.ts';
 
-async function onDownloadArchive(e) {
+async function onDownloadArchive(e: DOMEvent<MouseEvent>) {
   e.preventDefault();
   // there are many places using the "archive-link", eg: the dropdown on the repo code page, the release list
-  const el = e.target.closest('a.archive-link[href]');
+  const el = e.target.closest<HTMLAnchorElement>('a.archive-link[href]');
   const targetLoading = el.closest('.ui.dropdown') ?? el;
   targetLoading.classList.add('is-loading', 'loading-icon-2px');
   try {
@@ -107,7 +107,7 @@ export function initRepoCloneButtons() {
   queryElems(document, '.clone-buttons-combo', initCloneSchemeUrlSelection);
 }
 
-export async function updateIssuesMeta(url, action, issue_ids, id) {
+export async function updateIssuesMeta(url: string, action: string, issue_ids: string, id: string) {
   try {
     const response = await POST(url, {data: new URLSearchParams({action, issue_ids, id})});
     if (!response.ok) {
diff --git a/web_src/js/features/repo-diff.ts b/web_src/js/features/repo-diff.ts
index 0cb2e566c0..0dad4da862 100644
--- a/web_src/js/features/repo-diff.ts
+++ b/web_src/js/features/repo-diff.ts
@@ -168,7 +168,7 @@ function onShowMoreFiles() {
   initDiffHeaderPopup();
 }
 
-export async function loadMoreFiles(url) {
+export async function loadMoreFiles(url: string) {
   const target = document.querySelector('a#diff-show-more-files');
   if (target?.classList.contains('disabled') || pageData.diffFileInfo.isLoadingNewData) {
     return;
diff --git a/web_src/js/features/repo-editor.ts b/web_src/js/features/repo-editor.ts
index d7097787d2..0f3fb7bbcf 100644
--- a/web_src/js/features/repo-editor.ts
+++ b/web_src/js/features/repo-editor.ts
@@ -168,7 +168,7 @@ export function initRepoEditor() {
       silent: true,
       dirtyClass: dirtyFileClass,
       fieldSelector: ':input:not(.commit-form-wrapper :input)',
-      change($form) {
+      change($form: any) {
         const dirty = $form[0]?.classList.contains(dirtyFileClass);
         commitButton.disabled = !dirty;
       },
diff --git a/web_src/js/features/repo-findfile.ts b/web_src/js/features/repo-findfile.ts
index 6500978bc8..59c827126f 100644
--- a/web_src/js/features/repo-findfile.ts
+++ b/web_src/js/features/repo-findfile.ts
@@ -4,13 +4,15 @@ import {pathEscapeSegments} from '../utils/url.ts';
 import {GET} from '../modules/fetch.ts';
 
 const threshold = 50;
-let files = [];
-let repoFindFileInput, repoFindFileTableBody, repoFindFileNoResult;
+let files: Array<string> = [];
+let repoFindFileInput: HTMLInputElement;
+let repoFindFileTableBody: HTMLElement;
+let repoFindFileNoResult: HTMLElement;
 
 // return the case-insensitive sub-match result as an array:  [unmatched, matched, unmatched, matched, ...]
 // res[even] is unmatched, res[odd] is matched, see unit tests for examples
 // argument subLower must be a lower-cased string.
-export function strSubMatch(full, subLower) {
+export function strSubMatch(full: string, subLower: string) {
   const res = [''];
   let i = 0, j = 0;
   const fullLower = full.toLowerCase();
@@ -38,7 +40,7 @@ export function strSubMatch(full, subLower) {
   return res;
 }
 
-export function calcMatchedWeight(matchResult) {
+export function calcMatchedWeight(matchResult: Array<any>) {
   let weight = 0;
   for (let i = 0; i < matchResult.length; i++) {
     if (i % 2 === 1) { // matches are on odd indices, see strSubMatch
@@ -49,7 +51,7 @@ export function calcMatchedWeight(matchResult) {
   return weight;
 }
 
-export function filterRepoFilesWeighted(files, filter) {
+export function filterRepoFilesWeighted(files: Array<string>, filter: string) {
   let filterResult = [];
   if (filter) {
     const filterLower = filter.toLowerCase();
@@ -71,7 +73,7 @@ export function filterRepoFilesWeighted(files, filter) {
   return filterResult;
 }
 
-function filterRepoFiles(filter) {
+function filterRepoFiles(filter: string) {
   const treeLink = repoFindFileInput.getAttribute('data-url-tree-link');
   repoFindFileTableBody.innerHTML = '';
 
diff --git a/web_src/js/features/repo-home.ts b/web_src/js/features/repo-home.ts
index 763f8e503f..04a1288626 100644
--- a/web_src/js/features/repo-home.ts
+++ b/web_src/js/features/repo-home.ts
@@ -92,7 +92,7 @@ export function initRepoTopicBar() {
       onResponse(this: any, res: any) {
         const formattedResponse = {
           success: false,
-          results: [],
+          results: [] as Array<Record<string, any>>,
         };
         const query = stripTags(this.urlData.query.trim());
         let found_query = false;
@@ -134,12 +134,12 @@ export function initRepoTopicBar() {
         return formattedResponse;
       },
     },
-    onLabelCreate(value) {
+    onLabelCreate(value: string) {
       value = value.toLowerCase().trim();
       this.attr('data-value', value).contents().first().replaceWith(value);
       return fomanticQuery(this);
     },
-    onAdd(addedValue, _addedText, $addedChoice) {
+    onAdd(addedValue: string, _addedText: any, $addedChoice: any) {
       addedValue = addedValue.toLowerCase().trim();
       $addedChoice[0].setAttribute('data-value', addedValue);
       $addedChoice[0].setAttribute('data-text', addedValue);
diff --git a/web_src/js/features/repo-issue-content.ts b/web_src/js/features/repo-issue-content.ts
index 2279c26beb..056b810be8 100644
--- a/web_src/js/features/repo-issue-content.ts
+++ b/web_src/js/features/repo-issue-content.ts
@@ -33,7 +33,7 @@ function showContentHistoryDetail(issueBaseUrl: string, commentId: string, histo
   $fomanticDropdownOptions.dropdown({
     showOnFocus: false,
     allowReselection: true,
-    async onChange(_value, _text, $item) {
+    async onChange(_value: string, _text: string, $item: any) {
       const optionItem = $item.data('option-item');
       if (optionItem === 'delete') {
         if (window.confirm(i18nTextDeleteFromHistoryConfirm)) {
@@ -115,7 +115,7 @@ function showContentHistoryMenu(issueBaseUrl: string, elCommentItem: Element, co
     onHide() {
       $fomanticDropdown.dropdown('change values', null);
     },
-    onChange(value, itemHtml, $item) {
+    onChange(value: string, itemHtml: string, $item: any) {
       if (value && !$item.find('[data-history-is-deleted=1]').length) {
         showContentHistoryDetail(issueBaseUrl, commentId, value, itemHtml);
       }
diff --git a/web_src/js/features/repo-issue-edit.ts b/web_src/js/features/repo-issue-edit.ts
index 38dfea4743..a3a13a156d 100644
--- a/web_src/js/features/repo-issue-edit.ts
+++ b/web_src/js/features/repo-issue-edit.ts
@@ -2,14 +2,14 @@ import {handleReply} from './repo-issue.ts';
 import {getComboMarkdownEditor, initComboMarkdownEditor, ComboMarkdownEditor} from './comp/ComboMarkdownEditor.ts';
 import {POST} from '../modules/fetch.ts';
 import {showErrorToast} from '../modules/toast.ts';
-import {hideElem, querySingleVisibleElem, showElem} from '../utils/dom.ts';
+import {hideElem, querySingleVisibleElem, showElem, type DOMEvent} from '../utils/dom.ts';
 import {attachRefIssueContextPopup} from './contextpopup.ts';
 import {initCommentContent, initMarkupContent} from '../markup/content.ts';
 import {triggerUploadStateChanged} from './comp/EditorUpload.ts';
 import {convertHtmlToMarkdown} from '../markup/html2markdown.ts';
 import {applyAreYouSure, reinitializeAreYouSure} from '../vendor/jquery.are-you-sure.ts';
 
-async function tryOnEditContent(e) {
+async function tryOnEditContent(e: DOMEvent<MouseEvent>) {
   const clickTarget = e.target.closest('.edit-content');
   if (!clickTarget) return;
 
@@ -21,14 +21,14 @@ async function tryOnEditContent(e) {
 
   let comboMarkdownEditor : ComboMarkdownEditor;
 
-  const cancelAndReset = (e) => {
+  const cancelAndReset = (e: Event) => {
     e.preventDefault();
     showElem(renderContent);
     hideElem(editContentZone);
     comboMarkdownEditor.dropzoneReloadFiles();
   };
 
-  const saveAndRefresh = async (e) => {
+  const saveAndRefresh = async (e: Event) => {
     e.preventDefault();
     // we are already in a form, do not bubble up to the document otherwise there will be other "form submit handlers"
     // at the moment, the form submit event conflicts with initRepoDiffConversationForm (global '.conversation-holder form' event handler)
@@ -60,7 +60,7 @@ async function tryOnEditContent(e) {
       } else {
         renderContent.innerHTML = data.content;
         rawContent.textContent = comboMarkdownEditor.value();
-        const refIssues = renderContent.querySelectorAll('p .ref-issue');
+        const refIssues = renderContent.querySelectorAll<HTMLElement>('p .ref-issue');
         attachRefIssueContextPopup(refIssues);
       }
       const content = segment;
@@ -125,7 +125,7 @@ function extractSelectedMarkdown(container: HTMLElement) {
   return convertHtmlToMarkdown(el);
 }
 
-async function tryOnQuoteReply(e) {
+async function tryOnQuoteReply(e: Event) {
   const clickTarget = (e.target as HTMLElement).closest('.quote-reply');
   if (!clickTarget) return;
 
@@ -139,7 +139,7 @@ async function tryOnQuoteReply(e) {
 
   let editor;
   if (clickTarget.classList.contains('quote-reply-diff')) {
-    const replyBtn = clickTarget.closest('.comment-code-cloud').querySelector('button.comment-form-reply');
+    const replyBtn = clickTarget.closest('.comment-code-cloud').querySelector<HTMLElement>('button.comment-form-reply');
     editor = await handleReply(replyBtn);
   } else {
     // for normal issue/comment page
diff --git a/web_src/js/features/repo-issue-list.ts b/web_src/js/features/repo-issue-list.ts
index 74d4362bfd..01d4bb6f78 100644
--- a/web_src/js/features/repo-issue-list.ts
+++ b/web_src/js/features/repo-issue-list.ts
@@ -7,6 +7,7 @@ import {createSortable} from '../modules/sortable.ts';
 import {DELETE, POST} from '../modules/fetch.ts';
 import {parseDom} from '../utils.ts';
 import {fomanticQuery} from '../modules/fomantic/base.ts';
+import type {SortableEvent} from 'sortablejs';
 
 function initRepoIssueListCheckboxes() {
   const issueSelectAll = document.querySelector<HTMLInputElement>('.issue-checkbox-all');
@@ -104,7 +105,7 @@ function initDropdownUserRemoteSearch(el: Element) {
   $searchDropdown.dropdown('setting', {
     fullTextSearch: true,
     selectOnKeydown: false,
-    action: (_text, value) => {
+    action: (_text: string, value: string) => {
       window.location.href = actionJumpUrl.replace('{username}', encodeURIComponent(value));
     },
   });
@@ -133,7 +134,7 @@ function initDropdownUserRemoteSearch(el: Element) {
     $searchDropdown.dropdown('setting', 'apiSettings', {
       cache: false,
       url: `${searchUrl}&q={query}`,
-      onResponse(resp) {
+      onResponse(resp: any) {
         // the content is provided by backend IssuePosters handler
         processedResults.length = 0;
         for (const item of resp.results) {
@@ -153,7 +154,7 @@ function initDropdownUserRemoteSearch(el: Element) {
   const dropdownSetup = {...$searchDropdown.dropdown('internal', 'setup')};
   const dropdownTemplates = $searchDropdown.dropdown('setting', 'templates');
   $searchDropdown.dropdown('internal', 'setup', dropdownSetup);
-  dropdownSetup.menu = function (values) {
+  dropdownSetup.menu = function (values: any) {
     // remove old dynamic items
     for (const el of elMenu.querySelectorAll(':scope > .dynamic-item')) {
       el.remove();
@@ -193,7 +194,7 @@ function initPinRemoveButton() {
   }
 }
 
-async function pinMoveEnd(e) {
+async function pinMoveEnd(e: SortableEvent) {
   const url = e.item.getAttribute('data-move-url');
   const id = Number(e.item.getAttribute('data-issue-id'));
   await POST(url, {data: {id, position: e.newIndex + 1}});
diff --git a/web_src/js/features/repo-issue-sidebar-combolist.ts b/web_src/js/features/repo-issue-sidebar-combolist.ts
index 24d620547f..8db2f7665f 100644
--- a/web_src/js/features/repo-issue-sidebar-combolist.ts
+++ b/web_src/js/features/repo-issue-sidebar-combolist.ts
@@ -46,7 +46,7 @@ class IssueSidebarComboList {
     return Array.from(this.elDropdown.querySelectorAll('.menu > .item.checked'), (el) => el.getAttribute('data-value'));
   }
 
-  updateUiList(changedValues) {
+  updateUiList(changedValues: Array<string>) {
     const elEmptyTip = this.elList.querySelector('.item.empty-list');
     queryElemChildren(this.elList, '.item:not(.empty-list)', (el) => el.remove());
     for (const value of changedValues) {
@@ -60,7 +60,7 @@ class IssueSidebarComboList {
     toggleElem(elEmptyTip, !hasItems);
   }
 
-  async updateToBackend(changedValues) {
+  async updateToBackend(changedValues: Array<string>) {
     if (this.updateAlgo === 'diff') {
       for (const value of this.initialValues) {
         if (!changedValues.includes(value)) {
@@ -93,7 +93,7 @@ class IssueSidebarComboList {
     }
   }
 
-  async onItemClick(e) {
+  async onItemClick(e: Event) {
     const elItem = (e.target as HTMLElement).closest('.item');
     if (!elItem) return;
     e.preventDefault();
diff --git a/web_src/js/features/repo-issue.ts b/web_src/js/features/repo-issue.ts
index d2a89682e8..a0cb875a87 100644
--- a/web_src/js/features/repo-issue.ts
+++ b/web_src/js/features/repo-issue.ts
@@ -32,8 +32,8 @@ export function initRepoIssueSidebarList() {
     fullTextSearch: true,
     apiSettings: {
       url: issueSearchUrl,
-      onResponse(response) {
-        const filteredResponse = {success: true, results: []};
+      onResponse(response: any) {
+        const filteredResponse = {success: true, results: [] as Array<Record<string, any>>};
         const currIssueId = $('#new-dependency-drop-list').data('issue-id');
         // Parse the response from the api to work with our dropdown
         $.each(response, (_i, issue) => {
@@ -247,7 +247,7 @@ export function initRepoPullRequestUpdate() {
   });
 
   $('.update-button > .dropdown').dropdown({
-    onChange(_text, _value, $choice) {
+    onChange(_text: string, _value: string, $choice: any) {
       const choiceEl = $choice[0];
       const url = choiceEl.getAttribute('data-do');
       if (url) {
@@ -298,8 +298,8 @@ export function initRepoIssueReferenceRepositorySearch() {
     .dropdown({
       apiSettings: {
         url: `${appSubUrl}/repo/search?q={query}&limit=20`,
-        onResponse(response) {
-          const filteredResponse = {success: true, results: []};
+        onResponse(response: any) {
+          const filteredResponse = {success: true, results: [] as Array<Record<string, any>>};
           $.each(response.data, (_r, repo) => {
             filteredResponse.results.push({
               name: htmlEscape(repo.repository.full_name),
@@ -310,7 +310,7 @@ export function initRepoIssueReferenceRepositorySearch() {
         },
         cache: false,
       },
-      onChange(_value, _text, $choice) {
+      onChange(_value: string, _text: string, $choice: any) {
         const $form = $choice.closest('form');
         if (!$form.length) return;
 
@@ -360,7 +360,7 @@ export function initRepoIssueComments() {
   });
 }
 
-export async function handleReply(el) {
+export async function handleReply(el: HTMLElement) {
   const form = el.closest('.comment-code-cloud').querySelector('.comment-form');
   const textarea = form.querySelector('textarea');
 
@@ -379,7 +379,7 @@ export function initRepoPullRequestReview() {
       const groupID = commentDiv.closest('div[id^="code-comments-"]')?.getAttribute('id');
       if (groupID && groupID.startsWith('code-comments-')) {
         const id = groupID.slice(14);
-        const ancestorDiffBox = commentDiv.closest('.diff-file-box');
+        const ancestorDiffBox = commentDiv.closest<HTMLElement>('.diff-file-box');
 
         hideElem(`#show-outdated-${id}`);
         showElem(`#code-comments-${id}, #code-preview-${id}, #hide-outdated-${id}`);
@@ -589,7 +589,7 @@ export function initRepoIssueBranchSelect() {
   });
 }
 
-async function initSingleCommentEditor($commentForm) {
+async function initSingleCommentEditor($commentForm: any) {
   // pages:
   // * normal new issue/pr page: no status-button, no comment-button (there is only a normal submit button which can submit empty content)
   // * issue/pr view page: with comment form, has status-button and comment-button
@@ -611,7 +611,7 @@ async function initSingleCommentEditor($commentForm) {
   syncUiState();
 }
 
-function initIssueTemplateCommentEditors($commentForm) {
+function initIssueTemplateCommentEditors($commentForm: any) {
   // pages:
   // * new issue with issue template
   const $comboFields = $commentForm.find('.combo-editor-dropzone');
diff --git a/web_src/js/features/repo-migrate.ts b/web_src/js/features/repo-migrate.ts
index b75289feec..0788f83215 100644
--- a/web_src/js/features/repo-migrate.ts
+++ b/web_src/js/features/repo-migrate.ts
@@ -1,11 +1,11 @@
-import {hideElem, showElem} from '../utils/dom.ts';
+import {hideElem, showElem, type DOMEvent} from '../utils/dom.ts';
 import {GET, POST} from '../modules/fetch.ts';
 
 export function initRepoMigrationStatusChecker() {
   const repoMigrating = document.querySelector('#repo_migrating');
   if (!repoMigrating) return;
 
-  document.querySelector('#repo_migrating_retry')?.addEventListener('click', doMigrationRetry);
+  document.querySelector<HTMLButtonElement>('#repo_migrating_retry')?.addEventListener('click', doMigrationRetry);
 
   const repoLink = repoMigrating.getAttribute('data-migrating-repo-link');
 
@@ -55,7 +55,7 @@ export function initRepoMigrationStatusChecker() {
   syncTaskStatus(); // no await
 }
 
-async function doMigrationRetry(e) {
+async function doMigrationRetry(e: DOMEvent<MouseEvent>) {
   await POST(e.target.getAttribute('data-migrating-task-retry-url'));
   window.location.reload();
 }
diff --git a/web_src/js/features/repo-new.ts b/web_src/js/features/repo-new.ts
index 8a77a77b4a..f2c5eba62c 100644
--- a/web_src/js/features/repo-new.ts
+++ b/web_src/js/features/repo-new.ts
@@ -23,7 +23,7 @@ function initRepoNewTemplateSearch(form: HTMLFormElement) {
     $dropdown.dropdown('setting', {
       apiSettings: {
         url: `${appSubUrl}/repo/search?q={query}&template=true&priority_owner_id=${inputRepoOwnerUid.value}`,
-        onResponse(response) {
+        onResponse(response: any) {
           const results = [];
           results.push({name: '', value: ''}); // empty item means not using template
           for (const tmplRepo of response.data) {
@@ -66,7 +66,7 @@ export function initRepoNew() {
     let help = form.querySelector(`.help[data-help-for-repo-name="${CSS.escape(inputRepoName.value)}"]`);
     if (!help) help = form.querySelector(`.help[data-help-for-repo-name=""]`);
     showElem(help);
-    const repoNamePreferPrivate = {'.profile': false, '.profile-private': true};
+    const repoNamePreferPrivate: Record<string, boolean> = {'.profile': false, '.profile-private': true};
     const preferPrivate = repoNamePreferPrivate[inputRepoName.value];
     // inputPrivate might be disabled because site admin "force private"
     if (preferPrivate !== undefined && !inputPrivate.closest('.disabled, [disabled]')) {
diff --git a/web_src/js/features/repo-settings.ts b/web_src/js/features/repo-settings.ts
index 7b3ab504cb..b61ef9a153 100644
--- a/web_src/js/features/repo-settings.ts
+++ b/web_src/js/features/repo-settings.ts
@@ -12,7 +12,7 @@ function initRepoSettingsCollaboration() {
   for (const dropdownEl of queryElems(document, '.page-content.repository .ui.dropdown.access-mode')) {
     const textEl = dropdownEl.querySelector(':scope > .text');
     $(dropdownEl).dropdown({
-      async action(text, value) {
+      async action(text: string, value: string) {
         dropdownEl.classList.add('is-loading', 'loading-icon-2px');
         const lastValue = dropdownEl.getAttribute('data-last-value');
         $(dropdownEl).dropdown('hide');
@@ -53,8 +53,8 @@ function initRepoSettingsSearchTeamBox() {
     apiSettings: {
       url: `${appSubUrl}/org/${searchTeamBox.getAttribute('data-org-name')}/teams/-/search?q={query}`,
       headers: {'X-Csrf-Token': csrfToken},
-      onResponse(response) {
-        const items = [];
+      onResponse(response: any) {
+        const items: Array<Record<string, any>> = [];
         $.each(response.data, (_i, item) => {
           items.push({
             title: item.name,
diff --git a/web_src/js/features/repo-wiki.ts b/web_src/js/features/repo-wiki.ts
index 484c628f9f..9ffa8a3275 100644
--- a/web_src/js/features/repo-wiki.ts
+++ b/web_src/js/features/repo-wiki.ts
@@ -70,7 +70,7 @@ async function initRepoWikiFormEditor() {
   });
 }
 
-function collapseWikiTocForMobile(collapse) {
+function collapseWikiTocForMobile(collapse: boolean) {
   if (collapse) {
     document.querySelector('.wiki-content-toc details')?.removeAttribute('open');
   }
diff --git a/web_src/js/features/stopwatch.ts b/web_src/js/features/stopwatch.ts
index 46168b2cd7..a5cd5ae7c4 100644
--- a/web_src/js/features/stopwatch.ts
+++ b/web_src/js/features/stopwatch.ts
@@ -38,7 +38,7 @@ export function initStopwatch() {
   }
 
   let usingPeriodicPoller = false;
-  const startPeriodicPoller = (timeout) => {
+  const startPeriodicPoller = (timeout: number) => {
     if (timeout <= 0 || !Number.isFinite(timeout)) return;
     usingPeriodicPoller = true;
     setTimeout(() => updateStopwatchWithCallback(startPeriodicPoller, timeout), timeout);
@@ -103,7 +103,7 @@ export function initStopwatch() {
   startPeriodicPoller(notificationSettings.MinTimeout);
 }
 
-async function updateStopwatchWithCallback(callback, timeout) {
+async function updateStopwatchWithCallback(callback: (timeout: number) => void, timeout: number) {
   const isSet = await updateStopwatch();
 
   if (!isSet) {
@@ -125,7 +125,7 @@ async function updateStopwatch() {
   return updateStopwatchData(data);
 }
 
-function updateStopwatchData(data) {
+function updateStopwatchData(data: any) {
   const watch = data[0];
   const btnEls = document.querySelectorAll('.active-stopwatch');
   if (!watch) {
diff --git a/web_src/js/features/tablesort.ts b/web_src/js/features/tablesort.ts
index 15ea358fa3..0648ffd067 100644
--- a/web_src/js/features/tablesort.ts
+++ b/web_src/js/features/tablesort.ts
@@ -9,7 +9,7 @@ export function initTableSort() {
   }
 }
 
-function tableSort(normSort, revSort, isDefault) {
+function tableSort(normSort: string, revSort: string, isDefault: string) {
   if (!normSort) return false;
   if (!revSort) revSort = '';
 
diff --git a/web_src/js/features/tribute.ts b/web_src/js/features/tribute.ts
index fa65bcbb28..de1c3e97cd 100644
--- a/web_src/js/features/tribute.ts
+++ b/web_src/js/features/tribute.ts
@@ -1,14 +1,16 @@
 import {emojiKeys, emojiHTML, emojiString} from './emoji.ts';
 import {htmlEscape} from 'escape-goat';
 
-function makeCollections({mentions, emoji}) {
-  const collections = [];
+type TributeItem = Record<string, any>;
 
-  if (emoji) {
-    collections.push({
+export async function attachTribute(element: HTMLElement) {
+  const {default: Tribute} = await import(/* webpackChunkName: "tribute" */'tributejs');
+
+  const collections = [
+    { // emojis
       trigger: ':',
       requireLeadingSpace: true,
-      values: (query, cb) => {
+      values: (query: string, cb: (matches: Array<string>) => void) => {
         const matches = [];
         for (const name of emojiKeys) {
           if (name.includes(query)) {
@@ -18,22 +20,18 @@ function makeCollections({mentions, emoji}) {
         }
         cb(matches);
       },
-      lookup: (item) => item,
-      selectTemplate: (item) => {
+      lookup: (item: TributeItem) => item,
+      selectTemplate: (item: TributeItem) => {
         if (item === undefined) return null;
         return emojiString(item.original);
       },
-      menuItemTemplate: (item) => {
+      menuItemTemplate: (item: TributeItem) => {
         return `<div class="tribute-item">${emojiHTML(item.original)}<span>${htmlEscape(item.original)}</span></div>`;
       },
-    });
-  }
-
-  if (mentions) {
-    collections.push({
+    }, { // mentions
       values: window.config.mentionValues ?? [],
       requireLeadingSpace: true,
-      menuItemTemplate: (item) => {
+      menuItemTemplate: (item: TributeItem) => {
         return `
           <div class="tribute-item">
             <img src="${htmlEscape(item.original.avatar)}" width="21" height="21"/>
@@ -42,15 +40,9 @@ function makeCollections({mentions, emoji}) {
           </div>
         `;
       },
-    });
-  }
+    },
+  ];
 
-  return collections;
-}
-
-export async function attachTribute(element, {mentions, emoji}) {
-  const {default: Tribute} = await import(/* webpackChunkName: "tribute" */'tributejs');
-  const collections = makeCollections({mentions, emoji});
   // @ts-expect-error TS2351: This expression is not constructable (strange, why)
   const tribute = new Tribute({collection: collections, noMatchTemplate: ''});
   tribute.attach(element);
diff --git a/web_src/js/features/user-auth-webauthn.ts b/web_src/js/features/user-auth-webauthn.ts
index 70516c280d..b9ab2e2088 100644
--- a/web_src/js/features/user-auth-webauthn.ts
+++ b/web_src/js/features/user-auth-webauthn.ts
@@ -114,7 +114,7 @@ async function login2FA() {
   }
 }
 
-async function verifyAssertion(assertedCredential) {
+async function verifyAssertion(assertedCredential: any) { // TODO: Credential type does not work
   // Move data into Arrays in case it is super long
   const authData = new Uint8Array(assertedCredential.response.authenticatorData);
   const clientDataJSON = new Uint8Array(assertedCredential.response.clientDataJSON);
@@ -148,7 +148,7 @@ async function verifyAssertion(assertedCredential) {
   window.location.href = reply?.redirect ?? `${appSubUrl}/`;
 }
 
-async function webauthnRegistered(newCredential) {
+async function webauthnRegistered(newCredential: any) { // TODO: Credential type does not work
   const attestationObject = new Uint8Array(newCredential.response.attestationObject);
   const clientDataJSON = new Uint8Array(newCredential.response.clientDataJSON);
   const rawId = new Uint8Array(newCredential.rawId);
diff --git a/web_src/js/markup/asciicast.ts b/web_src/js/markup/asciicast.ts
index 97b18743a1..9baae6ba85 100644
--- a/web_src/js/markup/asciicast.ts
+++ b/web_src/js/markup/asciicast.ts
@@ -3,6 +3,7 @@ export async function renderAsciicast() {
   if (!els.length) return;
 
   const [player] = await Promise.all([
+    // @ts-expect-error: module exports no types
     import(/* webpackChunkName: "asciinema-player" */'asciinema-player'),
     import(/* webpackChunkName: "asciinema-player" */'asciinema-player/dist/bundle/asciinema-player.css'),
   ]);
diff --git a/web_src/js/markup/html2markdown.ts b/web_src/js/markup/html2markdown.ts
index fc2083e86d..8c2d2f8c86 100644
--- a/web_src/js/markup/html2markdown.ts
+++ b/web_src/js/markup/html2markdown.ts
@@ -1,7 +1,9 @@
 import {htmlEscape} from 'escape-goat';
 
+type Processor = (el: HTMLElement) => string | HTMLElement | void;
+
 type Processors = {
-  [tagName: string]: (el: HTMLElement) => string | HTMLElement | void;
+  [tagName: string]: Processor;
 }
 
 type ProcessorContext = {
@@ -11,7 +13,7 @@ type ProcessorContext = {
 }
 
 function prepareProcessors(ctx:ProcessorContext): Processors {
-  const processors = {
+  const processors: Processors = {
     H1(el: HTMLElement) {
       const level = parseInt(el.tagName.slice(1));
       el.textContent = `${'#'.repeat(level)} ${el.textContent.trim()}`;
diff --git a/web_src/js/modules/fomantic/dropdown.ts b/web_src/js/modules/fomantic/dropdown.ts
index e479c79ee6..8736e041df 100644
--- a/web_src/js/modules/fomantic/dropdown.ts
+++ b/web_src/js/modules/fomantic/dropdown.ts
@@ -38,7 +38,7 @@ function ariaDropdownFn(this: any, ...args: Parameters<FomanticInitFunction>) {
 // the elements inside the dropdown menu item should not be focusable, the focus should always be on the dropdown primary element.
 function updateMenuItem(dropdown: HTMLElement, item: HTMLElement) {
   if (!item.id) item.id = generateAriaId();
-  item.setAttribute('role', dropdown[ariaPatchKey].listItemRole);
+  item.setAttribute('role', (dropdown as any)[ariaPatchKey].listItemRole);
   item.setAttribute('tabindex', '-1');
   for (const el of item.querySelectorAll('a, input, button')) el.setAttribute('tabindex', '-1');
 }
@@ -61,7 +61,7 @@ function updateSelectionLabel(label: HTMLElement) {
   }
 }
 
-function processMenuItems($dropdown, dropdownCall) {
+function processMenuItems($dropdown: any, dropdownCall: any) {
   const hideEmptyDividers = dropdownCall('setting', 'hideDividers') === 'empty';
   const itemsMenu = $dropdown[0].querySelector('.scrolling.menu') || $dropdown[0].querySelector('.menu');
   if (hideEmptyDividers) hideScopedEmptyDividers(itemsMenu);
@@ -143,7 +143,7 @@ function attachStaticElements(dropdown: HTMLElement, focusable: HTMLElement, men
   $(menu).find('> .item').each((_, item) => updateMenuItem(dropdown, item));
 
   // this role could only be changed after its content is ready, otherwise some browsers+readers (like Chrome+AppleVoice) crash
-  menu.setAttribute('role', dropdown[ariaPatchKey].listPopupRole);
+  menu.setAttribute('role', (dropdown as any)[ariaPatchKey].listPopupRole);
 
   // prepare selection label items
   for (const label of dropdown.querySelectorAll<HTMLElement>('.ui.label')) {
@@ -151,8 +151,8 @@ function attachStaticElements(dropdown: HTMLElement, focusable: HTMLElement, men
   }
 
   // make the primary element (focusable) aria-friendly
-  focusable.setAttribute('role', focusable.getAttribute('role') ?? dropdown[ariaPatchKey].focusableRole);
-  focusable.setAttribute('aria-haspopup', dropdown[ariaPatchKey].listPopupRole);
+  focusable.setAttribute('role', focusable.getAttribute('role') ?? (dropdown as any)[ariaPatchKey].focusableRole);
+  focusable.setAttribute('aria-haspopup', (dropdown as any)[ariaPatchKey].listPopupRole);
   focusable.setAttribute('aria-controls', menu.id);
   focusable.setAttribute('aria-expanded', 'false');
 
@@ -164,7 +164,7 @@ function attachStaticElements(dropdown: HTMLElement, focusable: HTMLElement, men
 }
 
 function attachInit(dropdown: HTMLElement) {
-  dropdown[ariaPatchKey] = {};
+  (dropdown as any)[ariaPatchKey] = {};
   if (dropdown.classList.contains('custom')) return;
 
   // Dropdown has 2 different focusing behaviors
@@ -204,9 +204,9 @@ function attachInit(dropdown: HTMLElement) {
   // Since #19861 we have prepared the "combobox" solution, but didn't get enough time to put it into practice and test before.
   const isComboBox = dropdown.querySelectorAll('input').length > 0;
 
-  dropdown[ariaPatchKey].focusableRole = isComboBox ? 'combobox' : 'menu';
-  dropdown[ariaPatchKey].listPopupRole = isComboBox ? 'listbox' : '';
-  dropdown[ariaPatchKey].listItemRole = isComboBox ? 'option' : 'menuitem';
+  (dropdown as any)[ariaPatchKey].focusableRole = isComboBox ? 'combobox' : 'menu';
+  (dropdown as any)[ariaPatchKey].listPopupRole = isComboBox ? 'listbox' : '';
+  (dropdown as any)[ariaPatchKey].listItemRole = isComboBox ? 'option' : 'menuitem';
 
   attachDomEvents(dropdown, focusable, menu);
   attachStaticElements(dropdown, focusable, menu);
@@ -229,7 +229,7 @@ function attachDomEvents(dropdown: HTMLElement, focusable: HTMLElement, menu: HT
     // if the popup is visible and has an active/selected item, use its id as aria-activedescendant
     if (menuVisible) {
       focusable.setAttribute('aria-activedescendant', active.id);
-    } else if (dropdown[ariaPatchKey].listPopupRole === 'menu') {
+    } else if ((dropdown as any)[ariaPatchKey].listPopupRole === 'menu') {
       // for menu, when the popup is hidden, no need to keep the aria-activedescendant, and clear the active/selected item
       focusable.removeAttribute('aria-activedescendant');
       active.classList.remove('active', 'selected');
@@ -253,7 +253,7 @@ function attachDomEvents(dropdown: HTMLElement, focusable: HTMLElement, menu: HT
   // when the popup is hiding, it's better to have a small "delay", because there is a Fomantic UI animation
   // without the delay for hiding, the UI will be somewhat laggy and sometimes may get stuck in the animation.
   const deferredRefreshAriaActiveItem = (delay = 0) => { setTimeout(refreshAriaActiveItem, delay) };
-  dropdown[ariaPatchKey].deferredRefreshAriaActiveItem = deferredRefreshAriaActiveItem;
+  (dropdown as any)[ariaPatchKey].deferredRefreshAriaActiveItem = deferredRefreshAriaActiveItem;
   dropdown.addEventListener('keyup', (e) => { if (e.key.startsWith('Arrow')) deferredRefreshAriaActiveItem(); });
 
   // if the dropdown has been opened by focus, do not trigger the next click event again.
@@ -363,7 +363,7 @@ function onResponseKeepSelectedItem(dropdown: typeof $|HTMLElement, selectedValu
   // then the dropdown only shows other items and will select another (wrong) one.
   // It can't be easily fix by using setTimeout(patch, 0) in `onResponse` because the `onResponse` is called before another `setTimeout(..., timeLeft)`
   // Fortunately, the "timeLeft" is controlled by "loadingDuration" which is always zero at the moment, so we can use `setTimeout(..., 10)`
-  const elDropdown = (dropdown instanceof HTMLElement) ? dropdown : dropdown[0];
+  const elDropdown = (dropdown instanceof HTMLElement) ? dropdown : (dropdown as any)[0];
   setTimeout(() => {
     queryElems(elDropdown, `.menu .item[data-value="${CSS.escape(selectedValue)}"].filtered`, (el) => el.classList.remove('filtered'));
     $(elDropdown).dropdown('set selected', selectedValue ?? '');
diff --git a/web_src/js/standalone/devtest.ts b/web_src/js/standalone/devtest.ts
index 3489697a2f..e6baf6c9ce 100644
--- a/web_src/js/standalone/devtest.ts
+++ b/web_src/js/standalone/devtest.ts
@@ -1,7 +1,7 @@
 import {showInfoToast, showWarningToast, showErrorToast} from '../modules/toast.ts';
 
 function initDevtestToast() {
-  const levelMap = {info: showInfoToast, warning: showWarningToast, error: showErrorToast};
+  const levelMap: Record<string, any> = {info: showInfoToast, warning: showWarningToast, error: showErrorToast};
   for (const el of document.querySelectorAll('.toast-test-button')) {
     el.addEventListener('click', () => {
       const level = el.getAttribute('data-toast-level');
diff --git a/web_src/js/svg.ts b/web_src/js/svg.ts
index 1dd6922abb..b193afb255 100644
--- a/web_src/js/svg.ts
+++ b/web_src/js/svg.ts
@@ -208,7 +208,7 @@ export const SvgIcon = defineComponent({
     let {svgOuter, svgInnerHtml} = svgParseOuterInner(this.name);
     // https://vuejs.org/guide/extras/render-function.html#creating-vnodes
     // the `^` is used for attr, set SVG attributes like 'width', `aria-hidden`, `viewBox`, etc
-    const attrs = {};
+    const attrs: Record<string, any> = {};
     for (const attr of svgOuter.attributes) {
       if (attr.name === 'class') continue;
       attrs[`^${attr.name}`] = attr.value;
diff --git a/web_src/js/types.ts b/web_src/js/types.ts
index e972994928..1b5e652f66 100644
--- a/web_src/js/types.ts
+++ b/web_src/js/types.ts
@@ -22,6 +22,8 @@ export type Config = {
   i18n: Record<string, string>,
 }
 
+export type IntervalId = ReturnType<typeof setInterval>;
+
 export type Intent = 'error' | 'warning' | 'info';
 
 export type RequestData = string | FormData | URLSearchParams | Record<string, any>;
diff --git a/web_src/js/utils.ts b/web_src/js/utils.ts
index 86bdd3790e..54f59a2c03 100644
--- a/web_src/js/utils.ts
+++ b/web_src/js/utils.ts
@@ -166,10 +166,10 @@ export function sleep(ms: number): Promise<void> {
   return new Promise((resolve) => setTimeout(resolve, ms));
 }
 
-export function isImageFile({name, type}: {name: string, type?: string}): boolean {
+export function isImageFile({name, type}: {name?: string, type?: string}): boolean {
   return /\.(avif|jpe?g|png|gif|webp|svg|heic)$/i.test(name || '') || type?.startsWith('image/');
 }
 
-export function isVideoFile({name, type}: {name: string, type?: string}): boolean {
+export function isVideoFile({name, type}: {name?: string, type?: string}): boolean {
   return /\.(mpe?g|mp4|mkv|webm)$/i.test(name || '') || type?.startsWith('video/');
 }
diff --git a/web_src/js/utils/dom.ts b/web_src/js/utils/dom.ts
index e24cb29bac..603f967b34 100644
--- a/web_src/js/utils/dom.ts
+++ b/web_src/js/utils/dom.ts
@@ -255,12 +255,12 @@ export function loadElem(el: LoadableElement, src: string) {
 // it can't use other transparent polyfill patches because PaleMoon also doesn't support "addEventListener(capture)"
 const needSubmitEventPolyfill = typeof SubmitEvent === 'undefined';
 
-export function submitEventSubmitter(e) {
+export function submitEventSubmitter(e: any) {
   e = e.originalEvent ?? e; // if the event is wrapped by jQuery, use "originalEvent", otherwise, use the event itself
   return needSubmitEventPolyfill ? (e.target._submitter || null) : e.submitter;
 }
 
-function submitEventPolyfillListener(e) {
+function submitEventPolyfillListener(e: DOMEvent<Event>) {
   const form = e.target.closest('form');
   if (!form) return;
   form._submitter = e.target.closest('button:not([type]), button[type="submit"], input[type="submit"]');
diff --git a/web_src/js/utils/image.test.ts b/web_src/js/utils/image.test.ts
index da0605f1d0..49856c891c 100644
--- a/web_src/js/utils/image.test.ts
+++ b/web_src/js/utils/image.test.ts
@@ -4,7 +4,7 @@ const pngNoPhys = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAAAAAA
 const pngPhys = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAIAAAD91JpzAAAACXBIWXMAABYlAAAWJQFJUiTwAAAAEElEQVQI12OQNZcAIgYIBQAL8gGxdzzM0A==';
 const pngEmpty = 'data:image/png;base64,';
 
-async function dataUriToBlob(datauri) {
+async function dataUriToBlob(datauri: string) {
   return await (await globalThis.fetch(datauri)).blob();
 }
 
diff --git a/web_src/js/utils/time.ts b/web_src/js/utils/time.ts
index 6951ebfedb..c63498345f 100644
--- a/web_src/js/utils/time.ts
+++ b/web_src/js/utils/time.ts
@@ -54,7 +54,7 @@ export type DayDataObject = {
 }
 
 export function fillEmptyStartDaysWithZeroes(startDays: number[], data: DayDataObject): DayData[] {
-  const result = {};
+  const result: Record<string, any> = {};
 
   for (const startDay of startDays) {
     result[startDay] = data[startDay] || {'week': startDay, 'additions': 0, 'deletions': 0, 'commits': 0};
diff --git a/web_src/js/webcomponents/absolute-date.ts b/web_src/js/webcomponents/absolute-date.ts
index 8eb1c3e37e..23a8606673 100644
--- a/web_src/js/webcomponents/absolute-date.ts
+++ b/web_src/js/webcomponents/absolute-date.ts
@@ -15,7 +15,7 @@ window.customElements.define('absolute-date', class extends HTMLElement {
   initialized = false;
 
   update = () => {
-    const opt: Intl.DateTimeFormatOptions = {};
+    const opt: Record<string, string> = {};
     for (const attr of ['year', 'month', 'weekday', 'day']) {
       if (this.getAttribute(attr)) opt[attr] = this.getAttribute(attr);
     }