refactor(core): de-duplicate bootstrap code between bootstrapApplication and bootstrapModule (#57060)

This commit de-duplicates the code for bootstrapping between
`bootstrapApplication` and `bootstrapModule`. A majority of the
bootstrap code was identical between the two, with some minor
differences that can be handled with a function overload.

PR Close #57060

packages/core/src/application/create_application.ts

@@ -6,34 +6,19 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Subscription} from 'rxjs';
-
-import {
-  internalProvideZoneChangeDetection,
-  PROVIDED_NG_ZONE,
-} from '../change_detection/scheduling/ng_zone_scheduling';
+import {internalProvideZoneChangeDetection} from '../change_detection/scheduling/ng_zone_scheduling';
 import {EnvironmentProviders, Provider, StaticProvider} from '../di/interface/provider';
 import {EnvironmentInjector} from '../di/r3_injector';
-import {ErrorHandler} from '../error_handler';
-import {RuntimeError, RuntimeErrorCode} from '../errors';
-import {DEFAULT_LOCALE_ID} from '../i18n/localization';
-import {LOCALE_ID} from '../i18n/tokens';
-import {ImagePerformanceWarning} from '../image_performance_warning';
 import {Type} from '../interface/type';
 import {createOrReusePlatformInjector} from '../platform/platform';
-import {PLATFORM_DESTROY_LISTENERS} from '../platform/platform_ref';
 import {assertStandaloneComponentType} from '../render3/errors';
-import {setLocaleId} from '../render3/i18n/i18n_locale_id';
 import {EnvironmentNgModuleRefAdapter} from '../render3/ng_module_ref';
 import {NgZone} from '../zone/ng_zone';
 
-import {ApplicationInitStatus} from './application_init';
 import {_callAndReportToErrorHandler, ApplicationRef} from './application_ref';
-import {
-  PROVIDED_ZONELESS,
-  ChangeDetectionScheduler,
-} from '../change_detection/scheduling/zoneless_scheduling';
+import {ChangeDetectionScheduler} from '../change_detection/scheduling/zoneless_scheduling';
 import {ChangeDetectionSchedulerImpl} from '../change_detection/scheduling/zoneless_scheduling_impl';
+import {bootstrap} from '../platform/bootstrap';
 
 /**
  * Internal create application API that implements the core application creation logic and optional
@@ -76,67 +61,11 @@ export function internalCreateApplication(config: {
       // happens after we get the NgZone instance from the Injector.
       runEnvironmentInitializers: false,
     });
-    const envInjector = adapter.injector;
-    const ngZone = envInjector.get(NgZone);
 
-    return ngZone.run(() => {
-      envInjector.resolveInjectorInitializers();
-      const exceptionHandler: ErrorHandler | null = envInjector.get(ErrorHandler, null);
-      if (typeof ngDevMode === 'undefined' || ngDevMode) {
-        if (!exceptionHandler) {
-          throw new RuntimeError(
-            RuntimeErrorCode.MISSING_REQUIRED_INJECTABLE_IN_BOOTSTRAP,
-            'No `ErrorHandler` found in the Dependency Injection tree.',
-          );
-        }
-        if (envInjector.get(PROVIDED_ZONELESS) && envInjector.get(PROVIDED_NG_ZONE)) {
-          throw new RuntimeError(
-            RuntimeErrorCode.PROVIDED_BOTH_ZONE_AND_ZONELESS,
-            'Invalid change detection configuration: ' +
-              'provideZoneChangeDetection and provideExperimentalZonelessChangeDetection cannot be used together.',
-          );
-        }
-      }
-
-      let onErrorSubscription: Subscription;
-      ngZone.runOutsideAngular(() => {
-        onErrorSubscription = ngZone.onError.subscribe({
-          next: (error: any) => {
-            exceptionHandler!.handleError(error);
-          },
-        });
-      });
-
-      // If the whole platform is destroyed, invoke the `destroy` method
-      // for all bootstrapped applications as well.
-      const destroyListener = () => envInjector.destroy();
-      const onPlatformDestroyListeners = platformInjector.get(PLATFORM_DESTROY_LISTENERS);
-      onPlatformDestroyListeners.add(destroyListener);
-
-      envInjector.onDestroy(() => {
-        onErrorSubscription.unsubscribe();
-        onPlatformDestroyListeners.delete(destroyListener);
-      });
-
-      return _callAndReportToErrorHandler(exceptionHandler!, ngZone, () => {
-        const initStatus = envInjector.get(ApplicationInitStatus);
-        initStatus.runInitializers();
-
-        return initStatus.donePromise.then(() => {
-          const localeId = envInjector.get(LOCALE_ID, DEFAULT_LOCALE_ID);
-          setLocaleId(localeId || DEFAULT_LOCALE_ID);
-
-          const appRef = envInjector.get(ApplicationRef);
-          if (rootComponent !== undefined) {
-            appRef.bootstrap(rootComponent);
-          }
-          if (typeof ngDevMode === 'undefined' || ngDevMode) {
-            const imagePerformanceService = envInjector.get(ImagePerformanceWarning);
-            imagePerformanceService.start();
-          }
-          return appRef;
-        });
-      });
+    return bootstrap({
+      r3Injector: adapter.injector,
+      platformInjector,
+      rootComponent,
     });
   } catch (e) {
     return Promise.reject(e);

packages/core/src/platform/bootstrap.ts

@@ -0,0 +1,159 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {Subscription} from 'rxjs';
+
+import {PROVIDED_NG_ZONE} from '../change_detection/scheduling/ng_zone_scheduling';
+import {EnvironmentInjector, R3Injector} from '../di/r3_injector';
+import {ErrorHandler} from '../error_handler';
+import {RuntimeError, RuntimeErrorCode} from '../errors';
+import {DEFAULT_LOCALE_ID} from '../i18n/localization';
+import {LOCALE_ID} from '../i18n/tokens';
+import {ImagePerformanceWarning} from '../image_performance_warning';
+import {Type} from '../interface/type';
+import {PLATFORM_DESTROY_LISTENERS} from './platform_destroy_listeners';
+import {setLocaleId} from '../render3/i18n/i18n_locale_id';
+import {NgZone} from '../zone/ng_zone';
+
+import {ApplicationInitStatus} from '../application/application_init';
+import {_callAndReportToErrorHandler, ApplicationRef, remove} from '../application/application_ref';
+import {PROVIDED_ZONELESS} from '../change_detection/scheduling/zoneless_scheduling';
+import {Injector} from '../di';
+import {InternalNgModuleRef, NgModuleRef} from '../linker/ng_module_factory';
+import {stringify} from '../util/stringify';
+
+export interface ModuleBootstrapConfig<M> {
+  moduleRef: InternalNgModuleRef<M>;
+  allPlatformModules: NgModuleRef<unknown>[];
+}
+
+export interface ApplicationBootstrapConfig {
+  r3Injector: R3Injector;
+  platformInjector: Injector;
+  rootComponent: Type<unknown> | undefined;
+}
+
+function isApplicationBootstrapConfig(
+  config: ApplicationBootstrapConfig | ModuleBootstrapConfig<unknown>,
+): config is ApplicationBootstrapConfig {
+  return !!(config as ApplicationBootstrapConfig).platformInjector;
+}
+
+export function bootstrap<M>(
+  moduleBootstrapConfig: ModuleBootstrapConfig<M>,
+): Promise<NgModuleRef<M>>;
+export function bootstrap(
+  applicationBootstrapConfig: ApplicationBootstrapConfig,
+): Promise<ApplicationRef>;
+export function bootstrap<M>(
+  config: ModuleBootstrapConfig<M> | ApplicationBootstrapConfig,
+): Promise<ApplicationRef> | Promise<NgModuleRef<M>> {
+  const envInjector = isApplicationBootstrapConfig(config)
+    ? config.r3Injector
+    : config.moduleRef.injector;
+  const ngZone = envInjector.get(NgZone);
+  return ngZone.run(() => {
+    if (isApplicationBootstrapConfig(config)) {
+      config.r3Injector.resolveInjectorInitializers();
+    } else {
+      config.moduleRef.resolveInjectorInitializers();
+    }
+    const exceptionHandler = envInjector.get(ErrorHandler, null);
+    if (typeof ngDevMode === 'undefined' || ngDevMode) {
+      if (exceptionHandler === null) {
+        const errorMessage = isApplicationBootstrapConfig(config)
+          ? 'No `ErrorHandler` found in the Dependency Injection tree.'
+          : 'No ErrorHandler. Is platform module (BrowserModule) included';
+        throw new RuntimeError(
+          RuntimeErrorCode.MISSING_REQUIRED_INJECTABLE_IN_BOOTSTRAP,
+          errorMessage,
+        );
+      }
+      if (envInjector.get(PROVIDED_ZONELESS) && envInjector.get(PROVIDED_NG_ZONE)) {
+        throw new RuntimeError(
+          RuntimeErrorCode.PROVIDED_BOTH_ZONE_AND_ZONELESS,
+          'Invalid change detection configuration: ' +
+            'provideZoneChangeDetection and provideExperimentalZonelessChangeDetection cannot be used together.',
+        );
+      }
+    }
+
+    let onErrorSubscription: Subscription;
+    ngZone.runOutsideAngular(() => {
+      onErrorSubscription = ngZone.onError.subscribe({
+        next: (error: any) => {
+          exceptionHandler!.handleError(error);
+        },
+      });
+    });
+
+    if (isApplicationBootstrapConfig(config)) {
+      // If the whole platform is destroyed, invoke the `destroy` method
+      // for all bootstrapped applications as well.
+      const destroyListener = () => envInjector.destroy();
+      const onPlatformDestroyListeners = config.platformInjector.get(PLATFORM_DESTROY_LISTENERS);
+      onPlatformDestroyListeners.add(destroyListener);
+
+      envInjector.onDestroy(() => {
+        onErrorSubscription.unsubscribe();
+        onPlatformDestroyListeners.delete(destroyListener);
+      });
+    } else {
+      config.moduleRef.onDestroy(() => {
+        remove(config.allPlatformModules, config.moduleRef);
+        onErrorSubscription.unsubscribe();
+      });
+    }
+
+    return _callAndReportToErrorHandler(exceptionHandler!, ngZone, () => {
+      const initStatus = envInjector.get(ApplicationInitStatus);
+      initStatus.runInitializers();
+
+      return initStatus.donePromise.then(() => {
+        // If the `LOCALE_ID` provider is defined at bootstrap then we set the value for ivy
+        const localeId = envInjector.get(LOCALE_ID, DEFAULT_LOCALE_ID);
+        setLocaleId(localeId || DEFAULT_LOCALE_ID);
+
+        if (isApplicationBootstrapConfig(config)) {
+          const appRef = envInjector.get(ApplicationRef);
+          if (config.rootComponent !== undefined) {
+            appRef.bootstrap(config.rootComponent);
+          }
+          if (typeof ngDevMode === 'undefined' || ngDevMode) {
+            const imagePerformanceService = envInjector.get(ImagePerformanceWarning);
+            imagePerformanceService.start();
+          }
+          return appRef;
+        } else {
+          moduleDoBootstrap(config.moduleRef, config.allPlatformModules);
+          return config.moduleRef;
+        }
+      });
+    });
+  });
+}
+
+function moduleDoBootstrap(
+  moduleRef: InternalNgModuleRef<any>,
+  allPlatformModules: NgModuleRef<unknown>[],
+): void {
+  const appRef = moduleRef.injector.get(ApplicationRef);
+  if (moduleRef._bootstrapComponents.length > 0) {
+    moduleRef._bootstrapComponents.forEach((f) => appRef.bootstrap(f));
+  } else if (moduleRef.instance.ngDoBootstrap) {
+    moduleRef.instance.ngDoBootstrap(appRef);
+  } else {
+    throw new RuntimeError(
+      RuntimeErrorCode.BOOTSTRAP_COMPONENTS_NOT_FOUND,
+      ngDevMode &&
+        `The module ${stringify(moduleRef.instance.constructor)} was bootstrapped, ` +
+          `but it does not declare "@NgModule.bootstrap" components nor a "ngDoBootstrap" method. ` +
+          `Please define one of these.`,
+    );
+  }
+  allPlatformModules.push(moduleRef);
+}

packages/core/src/platform/platform.ts

@@ -15,7 +15,8 @@ import {InjectionToken, Injector, StaticProvider} from '../di';
 import {INJECTOR_SCOPE} from '../di/scope';
 import {RuntimeError, RuntimeErrorCode} from '../errors';
 
-import {PLATFORM_DESTROY_LISTENERS, PlatformRef} from './platform_ref';
+import {PlatformRef} from './platform_ref';
+import {PLATFORM_DESTROY_LISTENERS} from './platform_destroy_listeners';
 
 let _platformInjector: Injector | null = null;
 

packages/core/src/platform/platform_destroy_listeners.ts

@@ -0,0 +1,19 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {InjectionToken} from '../di';
+
+/**
+ * Internal token that allows to register extra callbacks that should be invoked during the
+ * `PlatformRef.destroy` operation. This token is needed to avoid a direct reference to the
+ * `PlatformRef` class (i.e. register the callback via `PlatformRef.onDestroy`), thus making the
+ * entire class tree-shakeable.
+ */
+export const PLATFORM_DESTROY_LISTENERS = new InjectionToken<Set<VoidFunction>>(
+  ngDevMode ? 'PlatformDestroyListeners' : '',
+);

packages/core/src/platform/platform_ref.ts

@@ -6,47 +6,27 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {ApplicationInitStatus} from '../application/application_init';
 import {compileNgModuleFactory} from '../application/application_ngmodule_factory_compiler';
 import {
   _callAndReportToErrorHandler,
-  ApplicationRef,
   BootstrapOptions,
   optionsReducer,
-  remove,
 } from '../application/application_ref';
 import {
   getNgZoneOptions,
   internalProvideZoneChangeDetection,
-  PROVIDED_NG_ZONE,
 } from '../change_detection/scheduling/ng_zone_scheduling';
-import {
-  ChangeDetectionScheduler,
-  PROVIDED_ZONELESS,
-} from '../change_detection/scheduling/zoneless_scheduling';
+import {ChangeDetectionScheduler} from '../change_detection/scheduling/zoneless_scheduling';
 import {ChangeDetectionSchedulerImpl} from '../change_detection/scheduling/zoneless_scheduling_impl';
-import {Injectable, InjectionToken, Injector} from '../di';
-import {ErrorHandler} from '../error_handler';
+import {Injectable, Injector} from '../di';
 import {RuntimeError, RuntimeErrorCode} from '../errors';
-import {DEFAULT_LOCALE_ID} from '../i18n/localization';
-import {LOCALE_ID} from '../i18n/tokens';
 import {Type} from '../interface/type';
 import {CompilerOptions} from '../linker';
-import {InternalNgModuleRef, NgModuleFactory, NgModuleRef} from '../linker/ng_module_factory';
-import {setLocaleId} from '../render3';
+import {NgModuleFactory, NgModuleRef} from '../linker/ng_module_factory';
 import {createNgModuleRefWithProviders} from '../render3/ng_module_ref';
-import {stringify} from '../util/stringify';
-import {getNgZone, NgZone, NoopNgZone} from '../zone/ng_zone';
-
-/**
- * Internal token that allows to register extra callbacks that should be invoked during the
- * `PlatformRef.destroy` operation. This token is needed to avoid a direct reference to the
- * `PlatformRef` class (i.e. register the callback via `PlatformRef.onDestroy`), thus making the
- * entire class tree-shakeable.
- */
-export const PLATFORM_DESTROY_LISTENERS = new InjectionToken<Set<VoidFunction>>(
-  ngDevMode ? 'PlatformDestroyListeners' : '',
-);
+import {getNgZone, NgZone} from '../zone/ng_zone';
+import {bootstrap} from './bootstrap';
+import {PLATFORM_DESTROY_LISTENERS} from './platform_destroy_listeners';
 
 /**
  * The Angular platform is the entry point for Angular on a web page.
@@ -97,52 +77,8 @@ export class PlatformRef {
       this.injector,
       allAppProviders,
     );
-    const envInjector = moduleRef.injector;
-    const ngZone = envInjector.get(NgZone);
 
-    return ngZone.run(() => {
-      moduleRef.resolveInjectorInitializers();
-      const exceptionHandler = envInjector.get(ErrorHandler, null);
-      if (typeof ngDevMode === 'undefined' || ngDevMode) {
-        if (exceptionHandler === null) {
-          throw new RuntimeError(
-            RuntimeErrorCode.MISSING_REQUIRED_INJECTABLE_IN_BOOTSTRAP,
-            'No ErrorHandler. Is platform module (BrowserModule) included?',
-          );
-        }
-        if (envInjector.get(PROVIDED_ZONELESS) && envInjector.get(PROVIDED_NG_ZONE)) {
-          throw new RuntimeError(
-            RuntimeErrorCode.PROVIDED_BOTH_ZONE_AND_ZONELESS,
-            'Invalid change detection configuration: ' +
-              'provideZoneChangeDetection and provideExperimentalZonelessChangeDetection cannot be used together.',
-          );
-        }
-      }
-
-      ngZone.runOutsideAngular(() => {
-        const subscription = ngZone.onError.subscribe({
-          next: (error: any) => {
-            exceptionHandler!.handleError(error);
-          },
-        });
-        moduleRef.onDestroy(() => {
-          remove(this._modules, moduleRef);
-          subscription.unsubscribe();
-        });
-      });
-      return _callAndReportToErrorHandler(exceptionHandler!, ngZone, () => {
-        const initStatus = envInjector.get(ApplicationInitStatus);
-        initStatus.runInitializers();
-
-        return initStatus.donePromise.then(() => {
-          // If the `LOCALE_ID` provider is defined at bootstrap then we set the value for ivy
-          const localeId = envInjector.get(LOCALE_ID, DEFAULT_LOCALE_ID);
-          setLocaleId(localeId || DEFAULT_LOCALE_ID);
-          this._moduleDoBootstrap(moduleRef);
-          return moduleRef;
-        });
-      });
-    });
+    return bootstrap({moduleRef, allPlatformModules: this._modules});
   }
 
   /**
@@ -173,24 +109,6 @@ export class PlatformRef {
     );
   }
 
-  private _moduleDoBootstrap(moduleRef: InternalNgModuleRef<any>): void {
-    const appRef = moduleRef.injector.get(ApplicationRef);
-    if (moduleRef._bootstrapComponents.length > 0) {
-      moduleRef._bootstrapComponents.forEach((f) => appRef.bootstrap(f));
-    } else if (moduleRef.instance.ngDoBootstrap) {
-      moduleRef.instance.ngDoBootstrap(appRef);
-    } else {
-      throw new RuntimeError(
-        RuntimeErrorCode.BOOTSTRAP_COMPONENTS_NOT_FOUND,
-        ngDevMode &&
-          `The module ${stringify(moduleRef.instance.constructor)} was bootstrapped, ` +
-            `but it does not declare "@NgModule.bootstrap" components nor a "ngDoBootstrap" method. ` +
-            `Please define one of these.`,
-      );
-    }
-    this._modules.push(moduleRef);
-  }
-
   /**
    * Registers a listener to be called when the platform is destroyed.
    */