Question 1

How do you configure dynamic base href in Angular builds for different environments?

Accepted Answer

**Target Audience:** Developers deploying Angular apps behind sub-paths, reverse proxies or multi-tenant hosts. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every index.html and bundle detail below comes from running [Angular CLI](/interview-question/what-does-the-angular-cli-provide) 22.2.3 builds on a fresh ng new app; the router behaviour was verified by booting the example in jsdom; URL reso

Question 2

What is Angular and how does it differ from AngularJS?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview — assumes basic JavaScript, no Angular or AngularJS required. **Difficulty:** Easy > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. The output in section 5 was produced by compiling and running the example on Angular 22.2.3, and the default-behaviour claims in section 6 were read from the Angular 22.2.3 pa

Question 3

What does the Angular CLI provide?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview — no Angular experience needed. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Everything under "Verified" was produced by running Angular CLI 22.2.3 in a sandbox: ng new, ng generate --dry-run, ng serve, ng build, ng test and ng lint, with the real output quoted. ng add an

Question 4

What are standalone components?

Accepted Answer

**Target Audience:** Developers preparing for an Angular interview who know what a component is and have seen, or heard of, NgModules. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Everything under a "Verified" heading was compiled with ngc on Angular 22.2.3 and run; the lazy-loading log in section 5 came from a real provideRouter setup. ## 1. Why This Even Matters — A Story First Picture packing

Question 5

What is the fixture.detectChanges() method in Angular testing, and when should you call it?

Accepted Answer

**Target Audience:** Developers writing or reviewing Angular component tests; assumes you have seen a TestBed spec but not much more. **Difficulty:** Easy to Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer listens for. Every behaviour quoted below was produced by running the spec in the example with Angular CLI 22.2.3 (ng test --watch=false, Vitest + jsdom), in the default zoneles

Question 6

What is the APP_INITIALIZER token and how is it used to load configuration at startup?

Accepted Answer

**Target Audience:** Developers wiring up real deployments, where configuration has to be known before the app can do anything useful. **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. The timing logs in section 5 were printed by the example booting on Angular 22.2.3 (with a fake HTTP backend, since no network is involved), and the deprecation fa

Question 7

How do functional interceptors work with provideHttpClient()?

Accepted Answer

**Target Audience:** Developers who can already write a basic interceptor and want to understand the chain well enough to debug ordering problems. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The internals described here were read from the installed @angular/common 22.2.3 source, and every ordering claim was produced by running instrumented interceptors (compiled with ngc, booted in jsdom with a

Question 8

How does catchError work in RxJS, and how do you return a fallback value?

Accepted Answer

**Target Audience:** Angular developers handling HTTP failures in RxJS pipelines, especially inside search boxes, effects and other long-lived streams. **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. Every behaviour in sections 3 to 6 was produced by running RxJS 7.8.2, and the component in section 7 was compiled and clicked through on Angular

Question 9

inject() vs constructor injection — when should you use each?

Accepted Answer

**Target Audience:** Developers and tech leads choosing a team convention, and candidates asked "which do you prefer and why?". **Difficulty:** Medium > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. This page is the *decision guide*. What each style compiles to, the injection-context rules and the inheritance mechanics are in the sibling question [constructor-based D

Question 10

What is the role of NgRx Effects, and why do we separate side effects from reducers?

Accepted Answer

**Target Audience:** Angular developers who know the basics of the NgRx store (actions, reducers, selectors) and want to understand where HTTP calls and other side effects belong. **Difficulty:** Medium to Hard > **How to read this doc:** Ideas are explained in plain language first, then tagged with 📌 Interview term: so you also learn the words an interviewer listens for. The action log in section 5, the error-handling run in section 6 and the effect test in section 7 were produce

ANGULARDECODED.

Easy

How do you configure dynamic base href in Angular builds for different environments?

What is Angular and how does it differ from AngularJS?

What does the Angular CLI provide?

What are standalone components?

What is the fixture.detectChanges() method in Angular testing, and when should you call it?

Medium

What is the APP_INITIALIZER token and how is it used to load configuration at startup?

How do functional interceptors work with provideHttpClient()?

How does catchError work in RxJS, and how do you return a fallback value?

inject() vs constructor injection — when should you use each?

What is the role of NgRx Effects, and why do we separate side effects from reducers?

How do you mock services in Angular unit tests using Jasmine/Jest spies?

What do @HostListener and @HostBinding do?

How do you handle errors and retries globally with interceptors?

Hard

What are security vulnerabilities in Angular apps, and how does DomSanitizer prevent XSS?

How do you handle micro-frontend architecture in Angular using Module Federation?

Signals signal()/computed()/effect() vs RxJS — when do you use which in Angular 18+?

How does change detection work in Angular?

How does compilation work under the hood in Ivy?

What is Angular Universal / SSR?

Explain the shareReplay operator in RxJS and how it prevents duplicate HTTP requests.

What is the difference between switchMap, mergeMap, concatMap, and exhaustMap?