Q: What is the difference between @ViewChildren and @ViewChild?

**Target Audience:** Developers who know @ViewChild and need to work with a list of matches: several inputs, a @for of child components, a set of tabs. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every "Verified" block was compiled with ngc (strict templates) on Angular 22.2.3 and run; compiled output was read from ngc itself. ## 1. Why This Even Matters — A Story Fir

Question 1

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 2

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 3

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 4

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 5

What are the types of data binding in Angular?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview — assumes HTML and a little TypeScript. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The outputs, compiler errors and the generated instructions quoted below all came from compiling the code with ngc on Angular 22.2.3 and running it in jsdom. ## 1. Why This Even Matters — A Story First Think of a component as a shop and the template as its shop w

Question 6

What is the difference between @ViewChildren and @ViewChild?

Accepted Answer

**Target Audience:** Developers who know @ViewChild and need to work with a list of matches: several inputs, a @for of child components, a set of tabs. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every "Verified" block was compiled with ngc (strict templates) on Angular 22.2.3 and run; compiled output was read from ngc itself. ## 1. Why This Even Matters — A Story Fir

Question 7

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

Accepted Answer

**Target Audience:** Developers moving component tests from @Input()/@Output() to the signal APIs (input(), model(), output(), computed(), effect()). **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. All results were produced by running the example spec with Angular CLI 22.2.3 (ng test --watch=false, Vitest, the default zon

Question 8

How do you handle SSR hydration mismatch errors using ngSkipHydration?

Accepted Answer

**Target Audience:** Developers who hit NG0500 hydration errors from a component they cannot easily rewrite. **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 example was AOT-compiled with ngc, rendered with renderApplication (Angular 22.2.3) and hydrated in jsdom, with and without ngSkipHydration; every

Question 9

What is a directive and what are the types?

Accepted Answer

**Target Audience:** Developers who use components daily and want a clear map of Angular's directive types, and how to write their own. **Difficulty:** Easy to Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The rendered output and event behaviour below were produced on Angular 22.2.3 by compiling the example with ngc (strict templates) and driving it in jsdom; the compiled definitions were read from ngc output an

Question 10

What are @ViewChild and @ContentChild?

Accepted Answer

**Target Audience:** Developers preparing for an Angular interview who have used #ref in a template and want to reach that element, or a child component, from the class. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every "Verified" block was compiled with ngc (strict templates) on Angular 22.2.3 and run; the decorator options are quoted from the installed typings. ## 1. Why This Even Matters —

ANGULARDECODED.

Easy

What are template reference variables?

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

How do child components emit events to parents?

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

What are the types of data binding in Angular?

Medium

What is the difference between @ViewChildren and @ViewChild?

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

How do you handle SSR hydration mismatch errors using ngSkipHydration?

What is a directive and what are the types?

What are @ViewChild and @ContentChild?

Explain the difference between Shadow DOM, Emulated, and None View Encapsulation with compile output.

What is the difference between reactive and template-driven forms?

What is trackBy in ngFor and why use it?

Hard

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

How does change detection work in Angular?

How does compilation work under the hood in Ivy?

How does SSR hydration work in Angular — non-destructive hydration and mismatches?

What is Angular Universal / SSR?

What is the difference between ElementRef, TemplateRef, and ViewContainerRef?

What is ViewEncapsulation in Angular?

What is the difference between afterRender and afterNextRender lifecycle hooks?