Add initializeAppCheck()`

Author: hsubox76

packages-exp/app-check-exp/src/api.ts

@@ -44,8 +44,34 @@ export function getAppCheck(app: FirebaseApp = getApp()): AppCheck {
     app,
     'app-check-exp'
   );
-  const appCheckInstance = appCheckProvider.getImmediate();
-  return appCheckInstance;
+
+  if (appCheckProvider.isInitialized()) {
+    return appCheckProvider.getImmediate();
+  }
+  return initializeAppCheck(app);
+}
+
+interface AppCheckOptions {
+  provider: AppCheckProvider;
+  isTokenAutoRefreshEnabled?: boolean;
+}
+
+export function initializeAppCheck(
+  app: FirebaseApp = getApp(),
+  options?: AppCheckOptions
+): AppCheck {
+  app = getModularInstance(app);
+  const provider = _getProvider(app, 'app-check-exp');
+
+  if (provider.isInitialized()) {
+    throw ERROR_FACTORY.create(AppCheckError.ALREADY_INITIALIZED, {
+      appName: app.name
+    });
+  }
+
+  const appCheck = provider.initialize({ options });
+
+  return appCheck;
 }
 
 /**

packages-exp/app-check-exp/src/errors.ts

@@ -19,6 +19,7 @@ import { ErrorFactory, ErrorMap } from '@firebase/util';
 
 export const enum AppCheckError {
   ALREADY_ACTIVATED = 'already-activated',
+  ALREADY_INITIALIZED = 'already-initialized',
   USE_BEFORE_ACTIVATION = 'use-before-activation',
   FETCH_NETWORK_ERROR = 'fetch-network-error',
   FETCH_PARSE_ERROR = 'fetch-parse-error',
@@ -34,6 +35,9 @@ const ERRORS: ErrorMap<AppCheckError> = {
     'You are trying to activate AppCheck for FirebaseApp {$appName}, ' +
     'while it is already activated. ' +
     'AppCheck can only be activated once.',
+  [AppCheckError.ALREADY_INITIALIZED]:
+    'You have already called initializeAppCheck() for FirebaseApp {$appName}, ' +
+    'initializeAppCheck() can only be called once.',
   [AppCheckError.USE_BEFORE_ACTIVATION]:
     'AppCheck is being used before activate() is called for FirebaseApp {$appName}. ' +
     'Please make sure you call activate() before instantiating other Firebase services.',
@@ -56,6 +60,7 @@ const ERRORS: ErrorMap<AppCheckError> = {
 
 interface ErrorParams {
   [AppCheckError.ALREADY_ACTIVATED]: { appName: string };
+  [AppCheckError.ALREADY_INITIALIZED]: { appName: string };
   [AppCheckError.USE_BEFORE_ACTIVATION]: { appName: string };
   [AppCheckError.FETCH_NETWORK_ERROR]: { originalErrorMessage: string };
   [AppCheckError.FETCH_PARSE_ERROR]: { originalErrorMessage: string };