Require localStorage or custom storage

Author: roncohen

packages/browser-sdk/src/flag/flags.ts

@@ -5,7 +5,7 @@ import { ReflagContext } from "../context";
 import { HttpClient } from "../httpClient";
 import { Logger, loggerWithPrefix } from "../logger";
 import RateLimiter from "../rateLimiter";
-import { resolveStorageAdapter, StorageAdapter } from "../storage";
+import { getLocalStorageAdapter, StorageAdapter } from "../storage";
 import { createEventTarget } from "../utils/eventTarget";
 
 import { FlagCache, isObject, parseAPIFlagsResponse } from "./flagCache";
@@ -234,11 +234,7 @@ export class FlagsClient {
     this.logger = loggerWithPrefix(logger, "[Flags]");
     this.rateLimiter =
       rateLimiter ?? new RateLimiter(FLAG_EVENTS_PER_MIN, this.logger);
-    const { adapter, type } = resolveStorageAdapter(
-      cache ? undefined : storage,
-    );
-    this.storage = adapter;
-    this.logger.debug(`storage adapter: ${type}`);
+    this.storage = (cache ? undefined : storage) ?? getLocalStorageAdapter();
     this.cache =
       cache ??
       this.setupCache(this.config.staleTimeMs, this.config.expireTimeMs);

packages/browser-sdk/src/storage.ts

@@ -4,62 +4,23 @@ export type StorageAdapter = {
   removeItem?(key: string): Promise<void>;
 };
 
-export type StorageAdapterType =
-  | "custom"
-  | "localStorage"
-  | "asyncStorage"
-  | "memory";
-
-export const createMemoryStorageAdapter = (): StorageAdapter => {
-  let value: string | null = null;
+export function getLocalStorageAdapter(): StorageAdapter {
+  if (
+    typeof localStorage === "undefined" ||
+    !("setItem" in localStorage) ||
+    !("removeItem" in localStorage)
+  ) {
+    throw new Error(
+      "localStorage is not available. Provide a custom storage adapter.",
+    );
+  }
   return {
-    getItem: async () => value,
-    setItem: async (_key, nextValue) => {
-      value = nextValue;
+    getItem: async (key) => localStorage.getItem(key),
+    setItem: async (key, value) => {
+      localStorage.setItem(key, value);
     },
-    removeItem: async () => {
-      value = null;
+    removeItem: async (key) => {
+      localStorage.removeItem(key);
     },
   };
-};
-
-function isLocalStorageUsable() {
-  return (
-    typeof localStorage !== "undefined" &&
-    "setItem" in localStorage &&
-    "removeItem" in localStorage
-  );
-}
-
-export function resolveStorageAdapter(storage?: StorageAdapter): {
-  adapter: StorageAdapter;
-  type: StorageAdapterType;
-} {
-  if (storage) return { adapter: storage, type: "custom" };
-  if (isLocalStorageUsable()) {
-    return {
-      adapter: {
-        getItem: async (key) => localStorage.getItem(key),
-        setItem: async (key, value) => {
-          localStorage.setItem(key, value);
-        },
-        removeItem: async (key) => {
-          localStorage.removeItem(key);
-        },
-      },
-      type: "localStorage",
-    };
-  }
-  // React Native: try AsyncStorage if available.
-  try {
-    // eslint-disable-next-line @typescript-eslint/no-require-imports
-    const asyncStorage = require("@react-native-async-storage/async-storage");
-    const adapter = asyncStorage?.default ?? asyncStorage;
-    if (adapter?.getItem && adapter?.setItem) {
-      return { adapter: adapter as StorageAdapter, type: "asyncStorage" };
-    }
-  } catch {
-    // ignore - not running in React Native or AsyncStorage not installed
-  }
-  return { adapter: createMemoryStorageAdapter(), type: "memory" };
 }