feat(router): Add the target RouterStateSnapshot to NavigationError (#46731)

This commit adds the target `RouterStateSnapshot` to the `NavigationError` so error handlers/subscribers can more easily determine which navigation failed, including the matched `Route` configs for the navigation. This information was previously not available (neither in `NavigationError` nor the `Router#getCurrentNavigation()`). fixes #27626 PR Close #46731

Author: atscott

goldens/public-api/router/index.md

@@ -388,9 +388,11 @@ export class NavigationError extends RouterEvent {
  constructor(
  id: number,
  url: string,
- error: any);
+ error: any,
+ target?: RouterStateSnapshot | undefined);
  // (undocumented)
  error: any;
+ readonly target?: RouterStateSnapshot | undefined;
  // (undocumented)
  toString(): string;
  // (undocumented)

packages/router/src/events.ts

@@ -244,7 +244,14 @@ export class NavigationError extends RouterEvent {
  /** @docsNotRequired */
  url: string,
  /** @docsNotRequired */
- public error: any) {
+ public error: any,
+ /**
+ * The target of the navigation when the error occurred.
+ *
+ * Note that this can be `undefined` because an error could have occurred before the
+ * `RouterStateSnapshot` was created for the navigation.
+ */
+ readonly target?: RouterStateSnapshot) {
  super(id, url);
  }
 

packages/router/src/router.ts

@@ -970,8 +970,9 @@ export class Router {
  * the pre-error state. */
  } else {
  this.restoreHistory(t, true);
- const navError =
- new NavigationError(t.id, this.serializeUrl(t.extractedUrl), e);
+ const navError = new NavigationError(
+ t.id, this.serializeUrl(t.extractedUrl), e,
+ t.targetSnapshot ?? undefined);
  eventsSubject.next(navError);
  try {
  t.resolve(this.errorHandler(e));