1 files changed, 36 insertions, 0 deletions
diff --git a/packages/frontend/src/scripts/idb-proxy.ts b/packages/frontend/src/scripts/idb-proxy.ts
new file mode 100644
index 0000000000..77bb84463c
--- /dev/null
+++ b/packages/frontend/src/scripts/idb-proxy.ts
@@ -0,0 +1,36 @@
+// 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) {
+	iset('idb-test', 'test').catch(err => {
+		console.error('idb error', err);
+		console.error('indexedDB is unavailable. It will use localStorage.');
+		idbAvailable = false;
+	});
+} else {
+	console.error('indexedDB is unavailable. It will use localStorage.');
+}
+
+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));
+}