feat(core): Make the isStandalone() function available in public API

This commit updates an internal `isStandalone` function and exposes it as a public API,
so that it can be used in applications code.

fixes #47919

goldens/public-api/core/errors.md

@@ -77,6 +77,8 @@ export const enum RuntimeErrorCode {
     // (undocumented)
     NO_SUPPORTING_DIFFER_FACTORY = 901,
     // (undocumented)
+    NON_ANNOTATED_CLASS = 911,
+    // (undocumented)
     PIPE_NOT_FOUND = -302,
     // (undocumented)
     PLATFORM_ALREADY_DESTROYED = 404,

goldens/public-api/core/index.md

@@ -787,6 +787,9 @@ export interface InputDecorator {
 // @public
 export function isDevMode(): boolean;
 
+// @public
+export function isStandalone<T>(type: Type<T>): boolean;
+
 // @public
 export interface IterableChangeRecord<V> {
     readonly currentIndex: number | null;

packages/core/src/core.ts

@@ -38,6 +38,7 @@ export {SecurityContext} from './sanitization/security';
 export {Sanitizer} from './sanitization/sanitizer';
 export {createNgModule, createNgModuleRef, createEnvironmentInjector} from './render3/ng_module_ref';
 export {createComponent, reflectComponentType, ComponentMirror} from './render3/component';
+export {isStandalone} from './render3/definition';
 
 import {global} from './util/global';
 if (typeof ngDevMode !== 'undefined' && ngDevMode) {

packages/core/src/core_render3_private_export.ts

@@ -248,7 +248,6 @@ export {
 export {
   compilePipe as ɵcompilePipe,
 } from './render3/jit/pipe';
-export { isStandalone as ɵisStandalone} from './render3/definition';
 export { Profiler as ɵProfiler, ProfilerEvent as ɵProfilerEvent } from './render3/profiler';
 export {
   publishDefaultGlobalUtils as ɵpublishDefaultGlobalUtils

packages/core/src/errors.ts

@@ -83,6 +83,7 @@ export const enum RuntimeErrorCode {
   MISSING_ZONEJS = 908,
   UNEXPECTED_ZONE_STATE = 909,
   UNSAFE_IFRAME_ATTRS = -910,
+  UNEXPECTED_CLASS_TYPE = 911,
 }
 
 /**

packages/core/src/render3/definition.ts

@@ -7,7 +7,7 @@
  */
 
 import {ChangeDetectionStrategy} from '../change_detection/constants';
-import {NG_PROV_DEF} from '../di/interface/defs';
+import {RuntimeError, RuntimeErrorCode} from '../errors';
 import {Mutable, Type} from '../interface/type';
 import {NgModuleDef} from '../metadata/ng_module_def';
 import {SchemaMetadata} from '../metadata/schema';
@@ -21,6 +21,7 @@ import {NG_COMP_DEF, NG_DIR_DEF, NG_MOD_DEF, NG_PIPE_DEF} from './fields';
 import {ComponentDef, ComponentDefFeature, ComponentTemplate, ComponentType, ContentQueriesFunction, DependencyTypeList, DirectiveDef, DirectiveDefFeature, DirectiveDefList, HostBindingsFunction, PipeDef, PipeDefList, TypeOrFactory, ViewQueriesFunction} from './interfaces/definition';
 import {TAttributes, TConstantsOrFactory} from './interfaces/node';
 import {CssSelectorList} from './interfaces/projection';
+import {stringifyForError} from './util/stringify_utils';
 
 
 /** Counter used to generate unique IDs for component definitions. */
@@ -741,9 +742,29 @@ export function getPipeDef<T>(type: any): PipeDef<T>|null {
   return type[NG_PIPE_DEF] || null;
 }
 
+/**
+ * Checks whether a given Component, Directive or Pipe is marked as standalone.
+ * See this guide for additional information: https://angular.io/guide/standalone-components
+ *
+ * @param type A reference to a Component, Directive or Pipe.
+ * @publicApi
+ */
 export function isStandalone<T>(type: Type<T>): boolean {
+  if (getNgModuleDef(type)) {
+    return false;
+  }
+
   const def = getComponentDef(type) || getDirectiveDef(type) || getPipeDef(type);
-  return def !== null ? def.standalone : false;
+  if (ngDevMode && def === null) {
+    throw new RuntimeError(
+        RuntimeErrorCode.UNEXPECTED_CLASS_TYPE,
+        `The \`isStandalone\` function supports Components, Directives and Pipes as an argument. ` +
+            `Make sure that the ${
+                stringifyForError(type)} class is annotated with the \`@Component\`, ` +
+            `\`@Directive\` or \`@Pipe\` decorator.`);
+  }
+
+  return def ? def.standalone : false;
 }
 
 export function getNgModuleDef<T>(type: any, throwNotFound: true): NgModuleDef<T>;

packages/core/src/render3/jit/module.ts

@@ -210,7 +210,10 @@ function verifySemanticsOfNgModuleDef(
   if (verifiedNgModule.get(moduleType)) return;
 
   // skip verifications of standalone components, directives, and pipes
-  if (isStandalone(moduleType)) return;
+  if ((getComponentDef(moduleType) || getPipeDef(moduleType) || getDirectiveDef(moduleType)) &&
+      isStandalone(moduleType)) {
+    return;
+  }
 
   verifiedNgModule.set(moduleType, true);
   moduleType = resolveForwardRef(moduleType);

packages/core/test/acceptance/standalone_spec.ts

@@ -7,7 +7,8 @@
  */
 
 import {CommonModule} from '@angular/common';
-import {Component, createEnvironmentInjector, Directive, EnvironmentInjector, forwardRef, Injector, Input, NgModule, NO_ERRORS_SCHEMA, OnInit, Pipe, PipeTransform, ViewChild, ViewContainerRef} from '@angular/core';
+import {Component, createEnvironmentInjector, Directive, EnvironmentInjector, forwardRef, Injector, Input, isStandalone, NgModule, NO_ERRORS_SCHEMA, OnInit, Pipe, PipeTransform, ViewChild, ViewContainerRef} from '@angular/core';
+import {RuntimeErrorCode} from '@angular/core/src/errors';
 import {TestBed} from '@angular/core/testing';
 
 describe('standalone components, directives, and pipes', () => {
@@ -847,4 +848,73 @@ describe('standalone components, directives, and pipes', () => {
       expect(fixture.nativeElement.textContent).toBe('');
     });
   });
+
+  describe('isStandalone()', () => {
+    it('should return `true` if component is standalone', () => {
+      @Component({selector: 'standalone-cmp', standalone: true})
+      class StandaloneCmp {
+      }
+
+      expect(isStandalone(StandaloneCmp)).toBeTrue();
+    });
+
+    it('should return `false` if component is not standalone', () => {
+      @Component({selector: 'standalone-cmp', standalone: false})
+      class StandaloneCmp {
+      }
+
+      expect(isStandalone(StandaloneCmp)).toBeFalse();
+    });
+
+    it('should return `true` if directive is standalone', () => {
+      @Directive({selector: '[standaloneDir]', standalone: true})
+      class StandAloneDirective {
+      }
+
+      expect(isStandalone(StandAloneDirective)).toBeTrue();
+    });
+
+    it('should return `false` if directive is standalone', () => {
+      @Directive({selector: '[standaloneDir]', standalone: false})
+      class StandAloneDirective {
+      }
+
+      expect(isStandalone(StandAloneDirective)).toBeFalse();
+    });
+
+    it('should return `true` if pipe is standalone', () => {
+      @Pipe({name: 'standalonePipe', standalone: true})
+      class StandAlonePipe {
+      }
+
+      expect(isStandalone(StandAlonePipe)).toBeTrue();
+    });
+
+    it('should return `false` if pipe is standalone', () => {
+      @Pipe({name: 'standalonePipe', standalone: false})
+      class StandAlonePipe {
+      }
+
+      expect(isStandalone(StandAlonePipe)).toBeFalse();
+    });
+
+    it('should throw when a non-annotated class is used as an argument', () => {
+      function getErrorMessageRegexp() {
+        const errorMessagePart =
+            'NG0' + Math.abs(RuntimeErrorCode.UNEXPECTED_CLASS_TYPE).toString();
+        return new RegExp(errorMessagePart);
+      }
+
+      class NonAnnotatedClass {}
+      expect(() => isStandalone(NonAnnotatedClass)).toThrowError(getErrorMessageRegexp());
+    });
+
+    it('should check wether an NgModule return false', () => {
+      @NgModule({})
+      class NgModuleA {
+      }
+
+      expect(isStandalone(NgModuleA)).toBeFalse();
+    });
+  });
 });

packages/core/test/bundling/animations/bundle.golden_symbols.json

@@ -842,6 +842,9 @@
   {
     "name": "getNextLContainer"
   },
+  {
+    "name": "getNgModuleDef"
+  },
   {
     "name": "getNodeInjectable"
   },
@@ -1310,6 +1313,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "style"
   },

packages/core/test/bundling/cyclic_import/bundle.golden_symbols.json

@@ -620,6 +620,9 @@
   {
     "name": "getNextLContainer"
   },
+  {
+    "name": "getNgModuleDef"
+  },
   {
     "name": "getNodeInjectable"
   },
@@ -989,6 +992,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "subscribeTo"
   },

packages/core/test/bundling/forms_reactive/bundle.golden_symbols.json

@@ -893,6 +893,9 @@
   {
     "name": "getNextLContainer"
   },
+  {
+    "name": "getNgModuleDef"
+  },
   {
     "name": "getNodeInjectable"
   },
@@ -1466,6 +1469,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "subscribeTo"
   },

packages/core/test/bundling/forms_template_driven/bundle.golden_symbols.json

@@ -854,6 +854,9 @@
   {
     "name": "getNextLContainer"
   },
+  {
+    "name": "getNgModuleDef"
+  },
   {
     "name": "getNodeInjectable"
   },
@@ -1442,6 +1445,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "subscribeTo"
   },

packages/core/test/bundling/hello_world/bundle.golden_symbols.json

@@ -113,6 +113,9 @@
   {
     "name": "NG_COMP_DEF"
   },
+  {
+    "name": "NG_DIR_DEF"
+  },
   {
     "name": "NG_ELEMENT_ID"
   },
@@ -131,6 +134,9 @@
   {
     "name": "NG_MOD_DEF"
   },
+  {
+    "name": "NG_PIPE_DEF"
+  },
   {
     "name": "NG_PROV_DEF"
   },
@@ -458,6 +464,9 @@
   {
     "name": "getNextLContainer"
   },
+  {
+    "name": "getNgModuleDef"
+  },
   {
     "name": "getNodeInjectable"
   },
@@ -749,6 +758,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "subscribeTo"
   },

packages/core/test/bundling/router/bundle.golden_symbols.json

@@ -1763,6 +1763,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "stripTrailingSlash"
   },

packages/core/test/bundling/standalone_bootstrap/bundle.golden_symbols.json

@@ -176,6 +176,9 @@
   {
     "name": "NG_INJ_DEF"
   },
+  {
+    "name": "NG_MOD_DEF"
+  },
   {
     "name": "NG_PIPE_DEF"
   },
@@ -842,6 +845,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "subscribeTo"
   },

packages/core/test/bundling/todo/bundle.golden_symbols.json

@@ -749,6 +749,9 @@
   {
     "name": "getNextLContainer"
   },
+  {
+    "name": "getNgModuleDef"
+  },
   {
     "name": "getNodeInjectable"
   },
@@ -1223,6 +1226,9 @@
   {
     "name": "stringifyCSSSelector"
   },
+  {
+    "name": "stringifyForError"
+  },
   {
     "name": "subscribeTo"
   },

packages/router/src/utils/config.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {createEnvironmentInjector, EnvironmentInjector, Type, ɵisStandalone as isStandalone, ɵRuntimeError as RuntimeError} from '@angular/core';
+import {createEnvironmentInjector, EnvironmentInjector, isStandalone, Type, ɵRuntimeError as RuntimeError} from '@angular/core';
 
 import {EmptyOutletComponent} from '../components/empty_outlet';
 import {RuntimeErrorCode} from '../errors';