A route parameter identifies a requested resource; it does not prove the resource exists or that the caller may access it. Angular interview questions about routing should cover loading, missing data and authorization boundaries as well as the happy path.

Use a public article route as an example. The ID comes from the URL, while static route data can describe the page's purpose. The component or resolver still needs a clear policy for retrieving the article.

What does a minimal route declare?

import { Routes } from '@angular/router';
import { ArticlePage } from './article-page';
import { NotFoundPage } from './not-found-page';

export const routes: Routes = [
  {
    path: 'articles/:id',
    component: ArticlePage,
    data: { section: 'Learning resources' }
  },
  { path: '**', component: NotFoundPage }
];

ArticlePage and NotFoundPage are application components, not built-in classes. Register routes through the application's supported router setup. Put the wildcard after the specific route so it acts as the fallback.

Is a snapshot always enough?

A snapshot is a point-in-time read. If the router reuses a component while the ID changes, a value read only during initialization may become stale. Subscribe to the parameter stream or use the version's supported reactive input mechanism when the component must react to parameter changes.

For HTTP retrieval, a switch-to-latest pattern can keep an older request from replacing newer navigation data. Handle loading and errors within that flow so one error does not unintentionally end all future parameter handling.

What can a resolver do?

A resolver can obtain required data before route activation. This can simplify the page but moves loading and failure behavior into navigation. Explain what the user sees while it waits and what happens on a missing article or dependency failure.

Do not catch every failure and return a plausible empty article. Missing content and temporary service failure need different outcomes. A page that looks successful with invented empty data can mislead users and diagnostics.

Does a guard secure the API?

No. A client-side guard can guide navigation and improve the interface. A caller can still send requests without running that guard. The server must enforce access to private resources and verify the authenticated context.

For a public article, an authentication guard may be unnecessary. Add a guard for an actual requirement rather than because every route example seems to include one. Keep the intended public search-engine access in mind.

How do you handle missing content?

Show a clear missing-article outcome and a useful route back to resources. For server-rendered public pages, the server should also return the appropriate HTTP status. A client-side “not found” message inside an unconditional 200 response does not establish correct server behavior.

Keep canonical URLs and metadata tied to the loaded article. Changing only the visible title while leaving another article's metadata can create misleading page identity.

Practice the route checks

  • Open a valid ID directly.
  • Navigate between two IDs while reusing the page.
  • Resolve a missing ID.
  • Simulate a dependency failure and recover on another navigation.
  • Open an unmatched path and confirm the wildcard behavior.
  • Check back and forward navigation.

A good answer follows both the URL and its data over time. The route declaration starts the story; loading, failure and server behavior complete it.

References and next practice

angular.dev — ng router

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