accountsストアはindexedDBで保持するように

src/client/scripts/get-account-from-id.ts

@@ -0,0 +1,7 @@
+import { get } from '@client/scripts/idb-proxy';
+
+export async function getAccountFromId(id: string) {
+	const accounts = await get('accounts') as { token: string; id: string; }[];
+	if (!accounts) console.log('Accounts are not recorded');
+	return accounts.find(e => e.id === id);
+}

src/client/scripts/idb-proxy.ts

@@ -0,0 +1,35 @@
+// FirefoxのプライベートモードなどではindexedDBが使用不可能なので、
+// indexedDBが使えない環境ではlocalStorageを使う
+import {
+	get as iget,
+	set as iset,
+	del as idel,
+} from 'idb-keyval';
+
+const fallbackName = (key: string) => `idbfallback::${key}`;
+
+let idbAvailable = typeof window !== 'undefined' ? !!window.indexedDB : true;
+
+if (idbAvailable) {
+	try {
+		const request = indexedDB.open('keyval-store');
+		if (request.error) idbAvailable = false;
+	} catch (e) {
+		idbAvailable = false;
+	}
+}
+
+export async function get(key: string) {
+	if (idbAvailable) return iget(key);
+	return JSON.parse(localStorage.getItem(fallbackName(key)));
+}
+
+export async function set(key: string, val: any) {
+	if (idbAvailable) return iset(key, val);
+	return localStorage.setItem(fallbackName(key), JSON.stringify(val));
+}
+
+export async function del(key: string) {
+	if (idbAvailable) return idel(key);
+	return localStorage.removeItem(fallbackName(key));
+}