Add demo library (books from Feedbooks)

apps/readest-app/src/utils/book.ts

@@ -1,6 +1,6 @@
 import { EXTS } from '@/libs/document';
 import { Book, BookConfig } from '@/types/book';
-import { makeSafeFilename } from './misc';
+import { getUserLang, makeSafeFilename } from './misc';
 
 export const getDir = (book: Book) => {
   return `${book.hash}`;
@@ -37,7 +37,7 @@ interface Contributor {
   name: LanguageMap;
 }
 
-const userLang = navigator?.language || 'en';
+const userLang = getUserLang();
 
 const formatLanguageMap = (x: string | LanguageMap): string => {
   if (!x) return '';

apps/readest-app/src/utils/misc.ts

@@ -23,6 +23,8 @@ export const makeSafeFilename = (filename: string, replacement = '_') => {
   return safeName.trim();
 };
 
+export const getUserLang = () => navigator?.language.split('-')[0] || 'en';
+
 export const getOSPlatform = () => {
   const userAgent = navigator.userAgent.toLowerCase();
 
@@ -34,3 +36,12 @@ export const getOSPlatform = () => {
 
   return '';
 };
+
+export const isValidURL = (url: string, allowedSchemes: string[] = ['http', 'https']) => {
+  try {
+    const { protocol } = new URL(url);
+    return allowedSchemes.some((scheme) => `${scheme}:` === protocol);
+  } catch {
+    return false;
+  }
+};