Angular interview Question

Explain what a JIT compilation is.

Explain the difference between JIT and AOT compilations.

Outline what the @Component decorator does.

Explain what services do in Angular.

Explain what Promises are in Angular.

Describe what Observables are in Angular.

Explain the Reactive forms method.

Explain what Bootstrap is.

Explain what Eager loading is.

Explain what Lazy loading is.

Explain what RxJS is.

5 advanced Angular interview questions and answers to evaluate senior developers
Evaluate your candidates’ knowledge and assess their responses to the five questions below by comparing them to our sample answers.

1. Explain what a JIT compilation is.
   Experienced applicants should know that JIT is short for just-in-time. A JIT compilation is a process that developers use to compile code during the execution of a program rather than before. Applicants may know that JIT is also called dynamic compilation.

2. Explain the difference between JIT and AOT compilations.
   While JIT works by downloading the compiler and compiling the code before displaying the output in the browser, AOT (ahead-of-time) will have already compiled the code during the application building process.

Applicants should know that AOT loading is faster than JIT because compilation in JIT happens at runtime.

1. Explain what services do in Angular. Can your applicants explain that services in Angular complete tasks that multiple components use? Services also complete operational tasks and ensure developers don’t have to rewrite code.

Can your applicants give examples of the tasks that Angular services complete, including image fetching and database management?

1. Explain what Promises are in Angular. Advanced Angular developers should know that Promises handle asynchronous events and emit one value at a time. Do they know that Promises execute straightaway after creation?

Your candidates may explain that Promises differ from Observables, which handle several asynchronous events over a certain time.

1. Explain the Reactive-form method. Can your applicants explain that the Reactive-form method is centered on data flows? Are they aware that using Reactive forms involves using the component to manage data flows directly?

Candidates should also know that Reactive forms work with code, which is different from the Template form method.

13 Angular interview questions about processes
Ask your developers some of these 13 Angular interview questions about processes to determine whether their knowledge will take your organization in the right direction.

13 Angular interview questions about processes
Explain what the ngOnChanges() lifecycle hook does.

Explain what the ngOnInit() lifecycle hook does.

Explain what the ngDoCheck() lifecycle hook does.

Explain what the ngAfterContentInit() lifecycle hook does.

Explain what the ngAfterContentChecked() lifecycle hook does.

Explain what the ngAfterViewChecked() lifecycle hook does.

Explain what the ngOnDestroy lifecycle hook does.

Explain how you would use the ngFor directive in a tag.

Explain what manual bootstrapping does.

Explain what automatic bootstrapping does.

Name three Angular building blocks and explain what they do.

Explain what the digest cycle process is in Angular.

Which approach would you use to create a service in Angular?

5 Angular interview questions and answers about processes to evaluate applicants
Evaluate your applicants’ responses to the following five Angular interview questions using the answers below as a guide.

1. Explain what manual bootstrapping does.
   Do your applicants know that manual bootstrapping helps developers initialize the app, giving them more control over the process? Can they explain that with this method, developers have extra flexibility to complete other operations before the page compilation process?

2. Which approach would you use to create a service in Angular?
   Applicants should know that there are different ways to create a service in Angular.

Developers can specify the providedIn property by using @Injectable decorator. For instance, they can register the articleService at the root level and specify this in the code. Doing this will mean that Angular will create a single service-class instance and use this instance for any class that uses it.

Candidates may also explain that if they need to reduce the service class’s scope, developers can register it inside the @Component decorator in the provider’s property.

1. Name three Angular building blocks and explain what they do. Three important Angular building blocks your applicants may name in response to this Angular interview question include:

Dependency injection: Developers use dependency injection to provide the new components with the required dependencies.

Services: This building block has several properties, including values, features, and functions, which contribute to the successful building of Angular applications.

Components: Components can control various views (different parts of the screen). The components feature the application logic that developers define in a class.

1. Explain how you would use the ngFor directive in a tag.
   Are your applicants aware that developers use the ngFor directive to create tables and lists in HTML templates? Can they explain that developers use the directive to iterate over an object and make templates? Your applicants may explain that developers can use the following code to use the ngFor directive:

2. Explain what the digest-cycle process is in Angular.
   Can your applicants explain that the digest cycle is a process where developers monitor a watchlist to track the changes that happen to a watch variable? Are they aware that developers can compare each version of the model values using each digest cycle?