refactor(core): make RuntimeError reusable across packages (#44398) (#44652)

This commit updates the code around the `RuntimeError` class to make it more reusable between packages (currently it's only usable inside the `core` package). Specifically:
- the error formatting logic was updated to handle cases when there is no error message provided
- there is no special Set that contains a set of error codes for which we have guides on angular.io. Instead, this is now encoded into the error code itself (making such codes negative integers). Having a separate Set makes it non-tree-shakable, which we want to avoid.

This change should allow to employ the `RuntimeError` class in other packages to further standardize this subsystem and make the errors thrown by the framework consistent.

As a part of the refactoring, the `common` package code was also updated to follow the same logic as `core`, since the `RuntimeError` class was used there as well.

PR Close #44398

PR Close #44652

packages/common/src/directives/ng_switch.ts

@@ -6,7 +6,9 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Directive, DoCheck, Host, Input, Optional, TemplateRef, ViewContainerRef, ɵRuntimeError as RuntimeError, ɵRuntimeErrorCode as RuntimeErrorCode} from '@angular/core';
+import {Directive, DoCheck, Host, Input, Optional, TemplateRef, ViewContainerRef, ɵRuntimeError as RuntimeError} from '@angular/core';
+
+import {RuntimeErrorCode} from '../errors';
 
 export class SwitchView {
   private _created = false;
@@ -243,7 +245,7 @@ export class NgSwitchDefault {
 
 function throwNgSwitchProviderNotFoundError(attrName: string, directiveName: string): never {
   throw new RuntimeError(
-      RuntimeErrorCode.TEMPLATE_STRUCTURE_ERROR,
+      RuntimeErrorCode.PARENT_NG_SWITCH_NOT_FOUND,
       `An element with the "${attrName}" attribute ` +
           `(matching the "${
               directiveName}" directive) must be located inside an element with the "ngSwitch" attribute ` +

packages/common/src/errors.ts

@@ -0,0 +1,16 @@
+/**
+ * @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
+ */
+
+/**
+ * The list of error codes used in runtime code of the `common` package.
+ * Reserved error code range: 2000-2999.
+ */
+export const enum RuntimeErrorCode {
+  // NgSwitch errors
+  PARENT_NG_SWITCH_NOT_FOUND = 2000,
+}

packages/common/test/directives/ng_switch_spec.ts

@@ -182,7 +182,7 @@ import {expect} from '@angular/platform-browser/testing/src/matchers';
 
            expect(() => createTestComponent(template))
                .toThrowError(
-                   'NG0305: An element with the "ngSwitchCase" attribute (matching the "NgSwitchCase" directive) must be located inside an element with the "ngSwitch" attribute (matching "NgSwitch" directive)');
+                   'NG02000: An element with the "ngSwitchCase" attribute (matching the "NgSwitchCase" directive) must be located inside an element with the "ngSwitch" attribute (matching "NgSwitch" directive)');
          }));
 
       it('should throw error when ngSwitchDefault is used outside of ngSwitch', waitForAsync(() => {
@@ -191,7 +191,7 @@ import {expect} from '@angular/platform-browser/testing/src/matchers';
 
            expect(() => createTestComponent(template))
                .toThrowError(
-                   'NG0305: An element with the "ngSwitchDefault" attribute (matching the "NgSwitchDefault" directive) must be located inside an element with the "ngSwitch" attribute (matching "NgSwitch" directive)');
+                   'NG02000: An element with the "ngSwitchDefault" attribute (matching the "NgSwitchDefault" directive) must be located inside an element with the "ngSwitch" attribute (matching "NgSwitch" directive)');
          }));
 
       it('should support nested NgSwitch on ng-container with ngTemplateOutlet', () => {

packages/core/src/core_private_export.ts

@@ -22,7 +22,7 @@ export {ComponentFactory as ɵComponentFactory} from './linker/component_factory
 export {clearResolutionOfComponentResourcesQueue as ɵclearResolutionOfComponentResourcesQueue, resolveComponentResources as ɵresolveComponentResources} from './metadata/resource_loading';
 export {ReflectionCapabilities as ɵReflectionCapabilities} from './reflection/reflection_capabilities';
 export {GetterFn as ɵGetterFn, MethodFn as ɵMethodFn, SetterFn as ɵSetterFn} from './reflection/types';
-export {RuntimeError as ɵRuntimeError, RuntimeErrorCode as ɵRuntimeErrorCode} from './render3/error_code';
+export {RuntimeError as ɵRuntimeError} from './render3/error_code';
 export {allowSanitizationBypassAndThrow as ɵallowSanitizationBypassAndThrow, BypassType as ɵBypassType, getSanitizationBypassType as ɵgetSanitizationBypassType, SafeHtml as ɵSafeHtml, SafeResourceUrl as ɵSafeResourceUrl, SafeScript as ɵSafeScript, SafeStyle as ɵSafeStyle, SafeUrl as ɵSafeUrl, SafeValue as ɵSafeValue, unwrapSafeValue as ɵunwrapSafeValue} from './sanitization/bypass';
 export {_sanitizeHtml as ɵ_sanitizeHtml} from './sanitization/html_sanitizer';
 export {_sanitizeUrl as ɵ_sanitizeUrl} from './sanitization/url_sanitizer';

packages/core/src/render3/error_code.ts

@@ -8,32 +8,40 @@
 
 import {ERROR_DETAILS_PAGE_BASE_URL} from './error_details_base_url';
 
+/**
+ * The list of error codes used in runtime code of the `core` package.
+ * Reserved error code range: 100-999.
+ *
+ * Note: the minus sign denotes the fact that a particular code has a detailed guide on
+ * angular.io. This extra annotation is needed to avoid introducing a separate set to store
+ * error codes which have guides, which might leak into runtime code.
+ *
+ * Full list of available error guides can be found at https://angular.io/errors.
+ */
 export const enum RuntimeErrorCode {
-  // Internal Errors
-
   // Change Detection Errors
-  EXPRESSION_CHANGED_AFTER_CHECKED = '100',
-  RECURSIVE_APPLICATION_REF_TICK = '101',
+  EXPRESSION_CHANGED_AFTER_CHECKED = -100,
+  RECURSIVE_APPLICATION_REF_TICK = 101,
 
   // Dependency Injection Errors
-  CYCLIC_DI_DEPENDENCY = '200',
-  PROVIDER_NOT_FOUND = '201',
+  CYCLIC_DI_DEPENDENCY = -200,
+  PROVIDER_NOT_FOUND = -201,
 
   // Template Errors
-  MULTIPLE_COMPONENTS_MATCH = '300',
-  EXPORT_NOT_FOUND = '301',
-  PIPE_NOT_FOUND = '302',
-  UNKNOWN_BINDING = '303',
-  UNKNOWN_ELEMENT = '304',
-  TEMPLATE_STRUCTURE_ERROR = '305',
+  MULTIPLE_COMPONENTS_MATCH = -300,
+  EXPORT_NOT_FOUND = -301,
+  PIPE_NOT_FOUND = -302,
+  UNKNOWN_BINDING = 303,
+  UNKNOWN_ELEMENT = 304,
+  TEMPLATE_STRUCTURE_ERROR = 305,
 
   // Bootstrap Errors
-  MULTIPLE_PLATFORMS = '400',
-  PLATFORM_NOT_FOUND = '401',
-  ERROR_HANDLER_NOT_FOUND = '402',
-  BOOTSTRAP_COMPONENTS_NOT_FOUND = '403',
-  ALREADY_DESTROYED_PLATFORM = '404',
-  ASYNC_INITIALIZERS_STILL_RUNNING = '405',
+  MULTIPLE_PLATFORMS = 400,
+  PLATFORM_NOT_FOUND = 401,
+  ERROR_HANDLER_NOT_FOUND = 402,
+  BOOTSTRAP_COMPONENTS_NOT_FOUND = 403,
+  ALREADY_DESTROYED_PLATFORM = 404,
+  ASYNC_INITIALIZERS_STILL_RUNNING = 405,
 
   // Styling Errors
 
@@ -41,42 +49,26 @@ export const enum RuntimeErrorCode {
 
   // i18n Errors
 
-  // Compilation Errors
+  // JIT Compilation Errors
 }
 
-export class RuntimeError extends Error {
-  constructor(public code: RuntimeErrorCode, message: string) {
-    super(formatRuntimeError(code, message));
+export class RuntimeError<T = RuntimeErrorCode> extends Error {
+  constructor(public code: T, message: string) {
+    super(formatRuntimeError<T>(code, message));
   }
 }
 
-// Contains a set of error messages that have details guides at angular.io.
-// Full list of available error guides can be found at https://angular.io/errors
-/* tslint:disable:no-toplevel-property-access */
-export const RUNTIME_ERRORS_WITH_GUIDES = new Set([
-  RuntimeErrorCode.EXPRESSION_CHANGED_AFTER_CHECKED,
-  RuntimeErrorCode.CYCLIC_DI_DEPENDENCY,
-  RuntimeErrorCode.PROVIDER_NOT_FOUND,
-  RuntimeErrorCode.MULTIPLE_COMPONENTS_MATCH,
-  RuntimeErrorCode.EXPORT_NOT_FOUND,
-  RuntimeErrorCode.PIPE_NOT_FOUND,
-]);
-/* tslint:enable:no-toplevel-property-access */
-
 /** Called to format a runtime error */
-export function formatRuntimeError(code: RuntimeErrorCode, message: string): string {
-  const fullCode = code ? `NG0${code}: ` : '';
+export function formatRuntimeError<T = RuntimeErrorCode>(code: T, message: string): string {
+  const codeAsNumber = code as unknown as number;
+  // Error code might be a negative number, which is a special marker that instructs the logic to
+  // generate a link to the error details page on angular.io.
+  const fullCode = `NG0${Math.abs(codeAsNumber)}`;
 
-  let errorMessage = `${fullCode}${message}`;
+  let errorMessage = `${fullCode}${message ? ': ' + message : ''}`;
 
-  // Some runtime errors are still thrown without `ngDevMode` (for example
-  // `throwProviderNotFoundError`), so we add `ngDevMode` check here to avoid pulling
-  // `RUNTIME_ERRORS_WITH_GUIDES` symbol into prod bundles.
-  // TODO: revisit all instances where `RuntimeError` is thrown and see if `ngDevMode` can be added
-  // there instead to tree-shake more devmode-only code (and eventually remove `ngDevMode` check
-  // from this code).
-  if (ngDevMode && RUNTIME_ERRORS_WITH_GUIDES.has(code)) {
-    errorMessage = `${errorMessage}. Find more at ${ERROR_DETAILS_PAGE_BASE_URL}/NG0${code}`;
+  if (ngDevMode && codeAsNumber < 0) {
+    errorMessage = `${errorMessage}. Find more at ${ERROR_DETAILS_PAGE_BASE_URL}/${fullCode}`;
   }
   return errorMessage;
 }

packages/core/src/render3/errors.ts

@@ -32,8 +32,6 @@ export function throwErrorIfNoChangesMode(
         ` It seems like the view has been created after its parent and its children have been dirty checked.` +
         ` Has it been created in a change detection hook?`;
   }
-  // TODO: include debug context, see `viewDebugError` function in
-  // `packages/core/src/view/errors.ts` for reference.
   throw new RuntimeError(RuntimeErrorCode.EXPRESSION_CHANGED_AFTER_CHECKED, msg);
 }
 

packages/core/src/render3/errors_di.ts

@@ -7,6 +7,7 @@
  */
 import {InjectorType} from '../di/interface/defs';
 import {stringify} from '../util/stringify';
+
 import {RuntimeError, RuntimeErrorCode} from './error_code';
 import {stringifyForError} from './util/stringify_utils';
 

packages/core/test/runtime_error_spec.ts

@@ -0,0 +1,32 @@
+/**
+ * @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 {RuntimeError, RuntimeErrorCode} from '../src/render3/error_code';
+
+describe('RuntimeError utils', () => {
+  it('should format the error message correctly', () => {
+    // Error with a guide, but without an error message.
+    let errorInstance = new RuntimeError(RuntimeErrorCode.EXPORT_NOT_FOUND, '');
+    expect(errorInstance.toString())
+        .toBe('Error: NG0301. Find more at https://angular.io/errors/NG0301');
+
+    // Error without a guide and an error message.
+    errorInstance = new RuntimeError(RuntimeErrorCode.TEMPLATE_STRUCTURE_ERROR, '');
+    expect(errorInstance.toString()).toBe('Error: NG0305');
+
+    // Error without a guide, but with an error message.
+    errorInstance =
+        new RuntimeError(RuntimeErrorCode.TEMPLATE_STRUCTURE_ERROR, 'Some error message');
+    expect(errorInstance.toString()).toBe('Error: NG0305: Some error message');
+
+    // Error with both a guide and an error message.
+    errorInstance = new RuntimeError(RuntimeErrorCode.EXPORT_NOT_FOUND, 'Some error message');
+    expect(errorInstance.toString())
+        .toBe('Error: NG0301: Some error message. Find more at https://angular.io/errors/NG0301');
+  });
+});