Q: Explain how you can bridge Signals and RxJS observables using toSignal() and toObservable().

**Target Audience:** Developers who already know what toSignal() and toObservable() do and want to use them confidently in production code — every option is explained before it is used. **Difficulty:** Medium to Hard > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every error message, type error and output below came from compiling with ngc (strict templates) on Angular 22.2.3 and running in jsdom, or from a

Question 1

What is the difference between computed() signals and standard method/getter calls in templates?

Accepted Answer

**Target Audience:** Developers who call methods in templates and want to know when it matters — assumes signals and basic change detection. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every call count below was produced by compiling the examples with ngc on Angular 22.2.3, running them in jsdom and clicking through them; both examples also passed the playground mode, so you can run them here. ## 1. Why Th

Question 2

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

Accepted Answer

**Target Audience:** Developers writing component and service tests who want to isolate a unit from its dependencies. **Difficulty:** Easy to Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The Vitest spec in the example was run with Angular CLI 22.2.3 (ng test --watch=false, Vitest 5, zoneless). The Jasmine spy behaviour was run in plain Jasmine 5.13 under Node, without Angular, to check the syntax and defaults; the Jest synt

Question 3

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

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview — assumes basic TypeScript and Angular components, no prior forms knowledge. **Difficulty:** Easy > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary interviewers listen for. The log lines in section 5 were produced by compiling the example with ngc (strict templates) on Angular 22.2.3, booting it in jsdom and typing into both forms with a test driver. ##

Question 4

What is the difference between Observables and Promises?

Accepted Answer

**Target Audience:** Anyone preparing for an Angular interview who has used async/await — assumes basic JavaScript, no RxJS required. **Difficulty:** Easy to Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every ordering claim below was produced by running a Node script against RxJS 7.8.2, and the component example was compiled with ngc on Angular 22.2.3 and clicked in jsdom. Execution order is the to

Question 5

How do you read route parameters?

Accepted Answer

**Target Audience:** Developers who have set up basic routes and now need data from the URL — assumes you know what a route and a component are. **Difficulty:** Easy to Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every log in sections 5 and 6 was produced by compiling the examples with ngc on Angular 22.2.3 and navigating between URLs with Router.navigateByUrl. Router defaults were read from the 22.2.3 package

Question 6

What does ChangeDetectorRef do?

Accepted Answer

**Target Audience:** Developers who know what a component is and want to control when its view updates — no internals knowledge assumed. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts with the vocabulary an interviewer expects. The method list was read from the Angular 22.2.3 typings, and every DOM snapshot below was produced by compiling and running the example on 22.2.3. ## 1. Why This Even Matters — A Story First Think

Question 7

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

Accepted Answer

**Target Audience:** Angular developers who have used both signals and Observables and want a principled rule for choosing — explains each idea from scratch. **Difficulty:** Medium > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. The comparison claims in section 5 come from a Node script run against @angular/core 22.2.3 and RxJS 7.8.2; the search example was compiled with ngc and driven in jsdom with real timers. Nothing

Question 8

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

Accepted Answer

**Target Audience:** Angular developers who fetch data with HttpClient and have seen the same request fire several times in the network tab. **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. Request counts and subscription logs in sections 4 to 6 were produced by running RxJS 7.8.2, the operator internals in section 3 were read from

Question 9

Explain how you can bridge Signals and RxJS observables using toSignal() and toObservable().

Accepted Answer

**Target Audience:** Developers who already know what toSignal() and toObservable() do and want to use them confidently in production code — every option is explained before it is used. **Difficulty:** Medium to Hard > **How to read this doc:** Plain language first, then 📌 Interview term: callouts. Every error message, type error and output below came from compiling with ngc (strict templates) on Angular 22.2.3 and running in jsdom, or from a

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