Question 1

Explain the new Control Flow (@if, @for, @switch) and how it compares to structural directives.

Accepted Answer

**Target Audience:** Developers who know basic Angular templates and want to understand what replaced *ngIf and *ngFor, 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. Every rendered output, compiler message and compiled instruction quoted below was produced on Angular 22.2.3: the examples were AOT-compiled wi

Question 2

What is the difference between the constructor and ngOnInit?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview who knows what a component and an input are. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The call order, the NG0950 runtime error and the NG8118 compiler error below were all produced by compiling and running the example on Angular 22.2.3. ## 1. Why This Even Matters — A Story First Think of a new employee's first day. Before they arrive, HR builds their des

Question 3

Explain the difference between FormGroup.patchValue() and FormGroup.setValue().

Accepted Answer

**Target Audience:** Developers who have built at least one reactive form and want to know exactly how its update methods behave. **Difficulty:** Easy to Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every error message and value quoted below was printed by running the code on Angular 22.2.3, either in the runnable example (compiled with ngc, booted in jsdom and clicked through by a driver) or in small scripts against

Question 4

What are template reference variables?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview who has written a basic template. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Each "Verified" block comes from compiling the example with ngc and strict templates on Angular 22.2.3 and clicking or typing through it in jsdom. ## 1. Why This Even Matters — A Story First At a busy party you can say "pass me the blue mug" and everyone at the table k

Question 5

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 6

What are components and modules in Angular?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview — assumes basic TypeScript classes, no Angular required. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer expects. Every output and error message quoted below was produced by compiling the code with ngc (strict templates) on Angular 22.2.3 and running it. ## 1. Why This Even Matters — A Story First Think of a restaur

Question 7

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 8

What is the purpose of ngOnChanges and how does it capture changes in @Input properties?

Accepted Answer

**Target Audience:** Developers preparing for an Angular interview who have written a component with an @Input and want to know exactly when Angular tells the component that the input changed. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer expects. Everything under a "Verified" heading was compiled with ngc (strict templates) on Angular 22.2.3 and run; the output

Question 9

How do child components emit events to parents?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview who knows what a component and an input are. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The call order in section 4 and the bubbling test in section 5 were produced by compiling the examples with ngc on Angular 22.2.3 and clicking through them in jsdom. ## 1. Why This Even Matters — A Story First A child at a school play does not walk into the

Question 10

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

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Easy

Explain the new Control Flow (@if, @for, @switch) and how it compares to structural directives.

What is the difference between the constructor and ngOnInit?

Explain the difference between FormGroup.patchValue() and FormGroup.setValue().

What are template reference variables?

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

What are components and modules in Angular?

What is Angular and how does it differ from AngularJS?

What is the purpose of ngOnChanges and how does it capture changes in @Input properties?

Medium

What is the difference between @ViewChildren and @ViewChild?

What is a route resolver and when is it useful?

Explain how to perform unit testing on components with Signals using TestBed.

How do you handle SSR hydration mismatch errors using ngSkipHydration?

What are route guards in Angular?

What is standard content projection vs. Multi-Slot Content Projection?

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

How do functional interceptors work with provideHttpClient()?

Hard

What is the difference between AOT and JIT compilation?

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

What are Deferrable Views (@defer) and how do they work in Angular 17+?

viewChild() signal queries vs @ViewChild decorator — what changed?

What does ChangeDetectorRef do?

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

What are signal inputs and model() in modern Angular?

What is the purpose of the KeyValueDiffers and IterableDiffers services?