Fix a number of Typescript issues (#31877)

Typescript error count is reduced from 633 to 540 with this. No runtime
changes except in test code.

web_src/js/utils.ts

@@ -1,13 +1,14 @@
 import {encode, decode} from 'uint8-to-base64';
+import type {IssueData} from './types.ts';
 
 // transform /path/to/file.ext to file.ext
-export function basename(path) {
+export function basename(path: string): string {
   const lastSlashIndex = path.lastIndexOf('/');
   return lastSlashIndex < 0 ? path : path.substring(lastSlashIndex + 1);
 }
 
 // transform /path/to/file.ext to .ext
-export function extname(path) {
+export function extname(path: string): string {
   const lastSlashIndex = path.lastIndexOf('/');
   const lastPointIndex = path.lastIndexOf('.');
   if (lastSlashIndex > lastPointIndex) return '';
@@ -15,54 +16,54 @@ export function extname(path) {
 }
 
 // test whether a variable is an object
-export function isObject(obj) {
+export function isObject(obj: any): boolean {
   return Object.prototype.toString.call(obj) === '[object Object]';
 }
 
 // returns whether a dark theme is enabled
-export function isDarkTheme() {
+export function isDarkTheme(): boolean {
   const style = window.getComputedStyle(document.documentElement);
   return style.getPropertyValue('--is-dark-theme').trim().toLowerCase() === 'true';
 }
 
 // strip <tags> from a string
-export function stripTags(text) {
+export function stripTags(text: string): string {
   return text.replace(/<[^>]*>?/g, '');
 }
 
-export function parseIssueHref(href) {
+export function parseIssueHref(href: string): IssueData {
   const path = (href || '').replace(/[#?].*$/, '');
   const [_, owner, repo, type, index] = /([^/]+)\/([^/]+)\/(issues|pulls)\/([0-9]+)/.exec(path) || [];
   return {owner, repo, type, index};
 }
 
 // parse a URL, either relative '/path' or absolute 'https://localhost/path'
-export function parseUrl(str) {
+export function parseUrl(str: string): URL {
   return new URL(str, str.startsWith('http') ? undefined : window.location.origin);
 }
 
 // return current locale chosen by user
-export function getCurrentLocale() {
+export function getCurrentLocale(): string {
   return document.documentElement.lang;
 }
 
 // given a month (0-11), returns it in the documents language
-export function translateMonth(month) {
+export function translateMonth(month: number) {
   return new Date(Date.UTC(2022, month, 12)).toLocaleString(getCurrentLocale(), {month: 'short', timeZone: 'UTC'});
 }
 
 // given a weekday (0-6, Sunday to Saturday), returns it in the documents language
-export function translateDay(day) {
+export function translateDay(day: number) {
   return new Date(Date.UTC(2022, 7, day)).toLocaleString(getCurrentLocale(), {weekday: 'short', timeZone: 'UTC'});
 }
 
 // convert a Blob to a DataURI
-export function blobToDataURI(blob) {
+export function blobToDataURI(blob: Blob): Promise<string> {
   return new Promise((resolve, reject) => {
     try {
       const reader = new FileReader();
       reader.addEventListener('load', (e) => {
-        resolve(e.target.result);
+        resolve(e.target.result as string);
       });
       reader.addEventListener('error', () => {
         reject(new Error('FileReader failed'));
@@ -75,7 +76,7 @@ export function blobToDataURI(blob) {
 }
 
 // convert image Blob to another mime-type format.
-export function convertImage(blob, mime) {
+export function convertImage(blob: Blob, mime: string): Promise<Blob> {
   return new Promise(async (resolve, reject) => {
     try {
       const img = new Image();
@@ -104,7 +105,7 @@ export function convertImage(blob, mime) {
   });
 }
 
-export function toAbsoluteUrl(url) {
+export function toAbsoluteUrl(url: string): string {
   if (url.startsWith('http://') || url.startsWith('https://')) {
     return url;
   }
@@ -118,15 +119,15 @@ export function toAbsoluteUrl(url) {
 }
 
 // Encode an ArrayBuffer into a URLEncoded base64 string.
-export function encodeURLEncodedBase64(arrayBuffer) {
+export function encodeURLEncodedBase64(arrayBuffer: ArrayBuffer): string {
   return encode(arrayBuffer)
     .replace(/\+/g, '-')
     .replace(/\//g, '_')
     .replace(/=/g, '');
 }
 
-// Decode a URLEncoded base64 to an ArrayBuffer string.
-export function decodeURLEncodedBase64(base64url) {
+// Decode a URLEncoded base64 to an ArrayBuffer.
+export function decodeURLEncodedBase64(base64url: string): ArrayBuffer {
   return decode(base64url
     .replace(/_/g, '/')
     .replace(/-/g, '+'));
@@ -135,20 +136,22 @@ export function decodeURLEncodedBase64(base64url) {
 const domParser = new DOMParser();
 const xmlSerializer = new XMLSerializer();
 
-export function parseDom(text, contentType) {
+export function parseDom(text: string, contentType: DOMParserSupportedType): Document {
   return domParser.parseFromString(text, contentType);
 }
 
-export function serializeXml(node) {
+export function serializeXml(node: Element | Node): string {
   return xmlSerializer.serializeToString(node);
 }
 
-export const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
+export function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
 
-export function isImageFile({name, type}) {
+export function isImageFile({name, type}: {name: string, type?: string}): boolean {
   return /\.(jpe?g|png|gif|webp|svg|heic)$/i.test(name || '') || type?.startsWith('image/');
 }
 
-export function isVideoFile({name, type}) {
+export function isVideoFile({name, type}: {name: string, type?: string}): boolean {
   return /\.(mpe?g|mp4|mkv|webm)$/i.test(name || '') || type?.startsWith('video/');
 }