fix: Eagerly initialize TurboModule because Proxies are slow

package/.eslintrc.js

@@ -1,7 +1,9 @@
 module.exports = {
   root: true,
   extends: ['@react-native', 'plugin:prettier/recommended'],
+  ignorePatterns: ['scripts', 'lib'],
   rules: {
     'prettier/prettier': ['warn'],
+    '@typescript-eslint/consistent-type-imports': 'warn',
   },
 };

package/example/ios/MmkvExample.xcodeproj/project.pbxproj

@@ -599,7 +599,10 @@
 					"-DFOLLY_HAVE_CLOCK_GETTIME=1",
 					"-DRN_FABRIC_ENABLED",
 				);
-				OTHER_LDFLAGS = "$(inherited)  ";
+				OTHER_LDFLAGS = (
+					"$(inherited)",
+					" ",
+				);
 				REACT_NATIVE_PATH = "${PODS_ROOT}/../../node_modules/react-native";
 				SDKROOT = iphoneos;
 				USE_HERMES = true;
@@ -676,7 +679,10 @@
 					"-DFOLLY_HAVE_CLOCK_GETTIME=1",
 					"-DRN_FABRIC_ENABLED",
 				);
-				OTHER_LDFLAGS = "$(inherited)  ";
+				OTHER_LDFLAGS = (
+					"$(inherited)",
+					" ",
+				);
 				REACT_NATIVE_PATH = "${PODS_ROOT}/../../node_modules/react-native";
 				SDKROOT = iphoneos;
 				USE_HERMES = true;

package/src/MMKV.ts

@@ -2,9 +2,9 @@ import { AppState } from 'react-native';
 import { createMMKV } from './createMMKV';
 import { createMockMMKV } from './createMMKV.mock';
 import { isTest } from './PlatformChecker';
-import { Configuration } from './NativeMmkv';
-import { Listener, MMKVInterface, NativeMMKV } from './Types';
-export { Configuration, Mode } from './NativeMmkv';
+import type { Configuration } from './NativeMmkv';
+import type { Listener, MMKVInterface, NativeMMKV } from './Types';
+export type { Configuration } from './NativeMmkv';
 
 const onValueChangedListeners = new Map<string, ((key: string) => void)[]>();
 

package/src/ModuleNotFoundError.ts

@@ -0,0 +1,95 @@
+import { NativeModules, Platform } from 'react-native';
+
+declare global {
+  // A react-native internal from TurboModuleRegistry.js
+  var __turboModuleProxy: unknown | undefined;
+}
+
+const BULLET_POINT = '\n* ';
+
+function messageWithSuggestions(
+  message: string,
+  suggestions: string[]
+): string {
+  return message + BULLET_POINT + suggestions.join(BULLET_POINT);
+}
+
+function getFrameworkType(): 'react-native' | 'expo' | 'expo-go' {
+  // check if Expo
+  const ExpoConstants =
+    NativeModules.NativeUnimoduleProxy?.modulesConstants?.ExponentConstants;
+  if (ExpoConstants != null) {
+    if (ExpoConstants.appOwnership === 'expo') {
+      // We're running Expo Go
+      return 'expo-go';
+    } else {
+      // We're running Expo bare / standalone
+      return 'expo';
+    }
+  }
+  return 'react-native';
+}
+
+export class ModuleNotFoundError extends Error {
+  constructor(cause?: unknown) {
+    // TurboModule not found, something went wrong!
+    if (global.__turboModuleProxy == null) {
+      // TurboModules are not available/new arch is not enabled.
+      // react-native-mmkv 3.x.x requires new arch (react-native >0.74)
+      // react-native-mmkv 2.x.x works on old arch (react-native <0.74)
+      const message =
+        'Failed to create a new MMKV instance: react-native-mmkv 3.x.x requires TurboModules, but the new architecture is not enabled!';
+      const suggestions: string[] = [];
+      suggestions.push(
+        'Downgrade to react-native-mmkv 2.x.x if you want to stay on the old architecture.'
+      );
+      suggestions.push(
+        'Enable the new architecture in your app to use react-native-mmkv 3.x.x. (See https://github.com/reactwg/react-native-new-architecture/blob/main/docs/enable-apps.md)'
+      );
+      const error = messageWithSuggestions(message, suggestions);
+      super(error, { cause: cause });
+      return;
+    }
+
+    const framework = getFrameworkType();
+    if (framework === 'expo-go') {
+      super(
+        'react-native-mmkv is not supported in Expo Go! Use EAS (`expo prebuild`) or eject to a bare workflow instead.'
+      );
+      return;
+    }
+
+    const message =
+      'Failed to create a new MMKV instance: The native MMKV Module could not be found.';
+    const suggestions: string[] = [];
+    suggestions.push(
+      'Make sure react-native-mmkv is correctly autolinked (run `npx react-native config` to verify)'
+    );
+    suggestions.push(
+      'Make sure you enabled the new architecture (TurboModules) and CodeGen properly generated the react-native-mmkv specs. See https://github.com/reactwg/react-native-new-architecture/blob/main/docs/enable-apps.md'
+    );
+    suggestions.push(
+      'Make sure you are using react-native 0.74.0 or higher, because react-native-mmkv is a C++ TurboModule.'
+    );
+    suggestions.push('Make sure you rebuilt the app.');
+    if (framework === 'expo') {
+      suggestions.push('Make sure you ran `expo prebuild`.');
+    }
+    switch (Platform.OS) {
+      case 'ios':
+      case 'macos':
+        suggestions.push(
+          'Make sure you ran `pod install` in the ios/ directory.'
+        );
+        break;
+      case 'android':
+        suggestions.push('Make sure gradle is synced.');
+        break;
+      default:
+        throw new Error(`MMKV is not supported on ${Platform.OS}!`);
+    }
+
+    const error = messageWithSuggestions(message, suggestions);
+    super(error, { cause: cause });
+  }
+}

package/src/NativeMmkv.ts

@@ -1,8 +1,8 @@
-import { TurboModule } from 'react-native';
+import type { TurboModule } from 'react-native';
 import { TurboModuleRegistry } from 'react-native';
-import { UnsafeObject } from 'react-native/Libraries/Types/CodegenTypes';
-import { getLazyTurboModule } from './LazyTurboModule';
-import { PlatformContext } from './NativeMmkvPlatformContext';
+import type { UnsafeObject } from 'react-native/Libraries/Types/CodegenTypes';
+import { ModuleNotFoundError } from './ModuleNotFoundError';
+import { getMMKVPlatformContextTurboModule } from './NativeMmkvPlatformContext';
 
 /**
  * Configures the mode of the MMKV instance.
@@ -85,21 +85,25 @@ export interface Spec extends TurboModule {
   createMMKV(configuration: Configuration): UnsafeObject;
 }
 
-let basePath: string | null = null;
+let module: Spec | null;
 
-function getNativeModule(): Spec | null {
-  if (basePath == null) {
-    // use default base path from the Platform (iOS/Android)
-    basePath = PlatformContext.getBaseDirectory();
-  }
+export function getMMKVTurboModule(): Spec {
+  try {
+    if (module == null) {
+      // 1. Load MMKV TurboModule
+      module = TurboModuleRegistry.getEnforcing<Spec>('MmkvCxx');
 
-  const module = TurboModuleRegistry.get<Spec>('MmkvCxx');
+      // 2. Get the PlatformContext TurboModule as well
+      const platformContext = getMMKVPlatformContextTurboModule();
 
-  if (module != null) {
-    // initialize MMKV
-    module.initialize(basePath);
-  }
+      // 3. Initialize it with the documents directory from platform-specific context
+      const basePath = platformContext.getBaseDirectory();
+      module.initialize(basePath);
+    }
 
-  return module;
+    return module;
+  } catch (cause) {
+    // TurboModule could not be found!
+    throw new ModuleNotFoundError(cause);
+  }
 }
-export const MMKVTurboModule = getLazyTurboModule(getNativeModule);

package/src/NativeMmkvPlatformContext.ts

@@ -1,5 +1,6 @@
-import { TurboModule, TurboModuleRegistry } from 'react-native';
-import { getLazyTurboModule } from './LazyTurboModule';
+import type { TurboModule } from 'react-native';
+import { TurboModuleRegistry } from 'react-native';
+import { ModuleNotFoundError } from './ModuleNotFoundError';
 
 export interface Spec extends TurboModule {
   /**
@@ -8,7 +9,17 @@ export interface Spec extends TurboModule {
   getBaseDirectory(): string;
 }
 
-function getModule(): Spec | null {
-  return TurboModuleRegistry.get<Spec>('MmkvPlatformContext');
+let module: Spec | null;
+
+export function getMMKVPlatformContextTurboModule(): Spec {
+  try {
+    if (module == null) {
+      // 1. Get the TurboModule
+      module = TurboModuleRegistry.getEnforcing<Spec>('MmkvPlatformContext');
+    }
+    return module;
+  } catch (e) {
+    // TurboModule could not be found!
+    throw new ModuleNotFoundError(e);
+  }
 }
-export const PlatformContext = getLazyTurboModule(getModule);

package/src/createMMKV.ts

@@ -1,9 +1,11 @@
 import type { Configuration } from './MMKV';
-import { MMKVTurboModule } from './NativeMmkv';
+import { getMMKVTurboModule } from './NativeMmkv';
 import type { NativeMMKV } from './Types';
 
 export const createMMKV = (config: Configuration): NativeMMKV => {
-  const instance = MMKVTurboModule.createMMKV(config);
+  const module = getMMKVTurboModule();
+
+  const instance = module.createMMKV(config);
   if (__DEV__) {
     if (typeof instance !== 'object' || instance == null) {
       throw new Error(

package/src/hooks.ts

@@ -1,5 +1,6 @@
 import { useRef, useState, useMemo, useCallback, useEffect } from 'react';
-import { MMKV, Configuration } from './MMKV';
+import type { Configuration } from './MMKV';
+import { MMKV } from './MMKV';
 
 function isConfigurationEqual(
   left?: Configuration,

package/src/index.ts

@@ -1,4 +1,4 @@
 export * from './MMKV';
 export * from './hooks';
 
-export { Mode, Configuration } from './NativeMmkv';
+export type { Mode, Configuration } from './NativeMmkv';

package/tsconfig.json

@@ -2,27 +2,36 @@
   "compilerOptions": {
     "rootDir": ".",
     "paths": {
-      "react-native-mmkv": ["./src/index"]
+      "react-native-mmkv": [
+        "./src/index"
+      ]
     },
     "allowUnreachableCode": false,
     "allowUnusedLabels": false,
     "esModuleInterop": true,
     "forceConsistentCasingInFileNames": true,
     "jsx": "react",
-    "lib": ["esnext", "DOM"],
+    "lib": [
+      "esnext",
+      "DOM"
+    ],
     "module": "esnext",
     "moduleResolution": "node",
     "noFallthroughCasesInSwitch": true,
     "noImplicitReturns": true,
-    "noImplicitUseStrict": false,
     "noStrictGenericChecks": false,
-    "noUncheckedIndexedAccess": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
+    "noUncheckedIndexedAccess": true,
     "resolveJsonModule": true,
     "skipLibCheck": true,
     "strict": true,
     "target": "esnext",
   },
-  "include": ["src"]
+  "include": [
+    "src",
+    ".eslintrc.js",
+    "babel.config.js",
+    "react-native.config.js",
+  ]
 }