MakStashkevich · February 11, 2025 15:28 · Feb 7, 2024
diff --git a/storage.ts b/storage.ts
@@ -0,0 +1,58 @@
+/**
+ * Checks if the specified Web Storage API exists and is accessible
+ * @param storage - Web Storage API
+ * @returns true, if the Web Storage API is accessible
+ */
+const isStorageEnabled = (storage?: Storage): storage is Storage => {
+  if (!storage) return false;
+  try {
+    const key = `__storage__test`;
+    storage.setItem(key, '');
+    storage.removeItem(key);
+    return true;
+  } catch {
+    return false;
+  }
+};
+
+/**
+ * Utilizes a `Map` cache backed Web Storage API when the specified Web Storage API isn't accessible
+ * @param storage - possible Web Storage API
+ * @returns a Web Storage API implementation
+ */
+const createStorage = (storage?: Storage): Storage => {
+  if (isStorageEnabled(storage)) {
+    return storage;
+  }
+
+  const storageFallbackCache = new Map<string, string>();
+
+  return {
+    clear(): void {
+      storageFallbackCache.clear();
+    },
+    getItem(key: string): string | null {
+      // eslint-disable-next-line unicorn/no-null
+      return storageFallbackCache.get(key) ?? null;
+    },
+    key(index: number): string | null {
+      // eslint-disable-next-line unicorn/no-null
+      return [...storageFallbackCache.values()][index] ?? null;
+    },
+    get length() {
+      return storageFallbackCache.size;
+    },
+    removeItem(key: string): void {
+      storageFallbackCache.delete(key);
+    },
+    setItem(key: string, value: string): void {
+      storageFallbackCache.set(key, value);
+    },
+  };
+};
+
+// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+export const localStorage = createStorage(window?.localStorage);
+
+// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+export const sessionStorage = createStorage(window?.sessionStorage);