chore: remove .expo extension in favor of generic fallback to legacy native module mechanism

Author: brentvatne

src/RCTAsyncStorage.expo.js

@@ -1,8 +1,20 @@
-const {NativeModules} = require('react-native');
+const {NativeModules, TurboModuleRegistry} = require('react-native');
+const shouldFallbackToLegacyNativeModule = require('./shouldFallbackToLegacyNativeModule');
 
-const RCTAsyncStorage =
+let RCTAsyncStorage =
   NativeModules.PlatformLocalStorage || // Support for external modules, like react-native-windows
   NativeModules.RNC_AsyncSQLiteDBStorage ||
   NativeModules.RNCAsyncStorage;
 
+if (!RCTAsyncStorage && shouldFallbackToLegacyNativeModule()) {
+  // TurboModuleRegistry falls back to NativeModules so we don't have to try go
+  // assign NativeModules' counterparts if TurboModuleRegistry would resolve
+  // with undefined.
+  if (TurboModuleRegistry) {
+    RCTAsyncStorage = TurboModuleRegistry.get('AsyncSQLiteDBStorage') || TurboModuleRegistry.get('AsyncLocalStorage');
+  } else {
+    RCTAsyncStorage = NativeModules.AsyncSQLiteDBStorage || NativeModules.AsyncLocalStorage;
+  }
+}
+
 export default RCTAsyncStorage;

src/RCTAsyncStorage.js

@@ -0,0 +1,20 @@
+const {NativeModules} = require('react-native');
+
+export default function shouldFallbackToLegacyNativeModule() {
+  const expoExecutionEnvironment = NativeModules.NativeUnimoduleProxy?.modulesConstants?.ExponentConstants?.executionEnvironment;
+
+  /**
+   * Expo managed apps don't include the @react-native-async-storage/async-storage
+   * native modules yet, but the API interface is the same, so we can use the version
+   * exported from React Native still.
+   *
+   * If in future releases (eg: @react-native-async-storage/async-storage >= 2.0.0) this
+   * will likely not be valid anymore, and the package will need to be included in the Expo SDK
+   * to continue to work.
+   */
+  if (expoExecutionEnvironment && ['storeClient', 'standalone'].includes(expoExecutionEnvironment)) {
+    return true;
+  }
+
+  return false;
+}