Thursday, October 7, 2021

Top 20 Angular interview questions and Answers for 1 to 2 Years Experienced

Angular is one of the earliest frontend frameworks. The framework came out in 2010 at a time when modern development was starting to take place. It was, then, known as AngularJS. The popularity of AngularJS increased rapidly and it became one of the top frontend frameworks in no time. But soon, new landscapes were introduced in development, especially in JavaScript. AngularJS could not cope with it and the core team realized they needed to make the necessary changes. The changes were huge and instead of creating a new version, they created a whole new framework called Angular 2. Since then, every new version of Angular is referred to as Angular.

Today, Angular is one of the most popular and widely used frontend frameworks. AngularJS is still in use. Though new frameworks like React and Vue are gaining popularity, Angular still occupies its position.

It still has a huge job market and Angular developers are in big demand. Moreover, the salary of a skilled Angular developer is very high. So, if you have Angular skills and knowledge, you should definitely look for opportunities.

Angular is a huge and vast framework. Unlike React and Vue, Angular is not limited to only one part of the development. It is quite big and its interviews can be tough. So in this article will list 20+ Angular questions that will help you clear the Angular interviews.


20+ Angular Framework Interview Questions for Fullstack Developers

Here is my list of common Angular questions for Fullstack Java and our developers. These questions test your knowledge of essential Angular concepts and their pros and cons. You can use these Angular questions to not only prepare for your interviews but also to quickly revise essential Angular concepts like how it works, what makes it a popular framework etc. 

1. What are the components in Angular? How to define a component in Angular?
A: The basic building blocks of an Angular application are called components. A component controls a part of the user interface of the application. Similar to Spring Framework, the @Component decorator is used to define a component in Angular.

2. What are the main objectives of a service? How to define a service?
A: The main object of service in Angular is to share data and functions with multiple components.
The @Injectable decorator is used to define a service in Angular.

3. What are the different ways of sharing data from a child component to a parent component?
A: One way to share data from the child to parent component is by using the @input decorator. Another way is by using @ViewChild decorator. We can also use the @Output decorator and EventEmitter together in such a case.

4. When will you use a directive?
A: Suppose, there is a situation in the application where several components are required to have the same functionalities. Instead of adding the same functionality to each component one by one, I will create a directive. This directive will have the functionality that is required by all the components. Then, I will import this directive to the components where it is required.

5. How to create component directives?
A: Unlike normal directives, a component directive is created using @Component decorator rather than @Directive decorator.

6. Name the types of compilation in Angular?
A: Just-in-Time (JIT) compilation and Ahead-of-Time (AOT) compilation.

7. What are the advantages and disadvantages of using Angular?
A: Advantages of using Angular:
1. It follows the proper MVC architecture.
2. It supports two-way data binding.
3. It supports RESTful services, dependency injection, and validations.
4. It has a huge community.
5. Useful features such as event handlers and animations are supported by Angular.

Disadvantages of using Angular are:
1. Angular is difficult to learn. Moreover, it requires Typescript.
2. Angular is huge so there are way too many concepts that can be confusing.
3. Angular is not recommended for small projects.
4. It does not provide much flexibility.
5. Newer frameworks like React and Vue are better performing than Angular.

8. Why is data-binding used?
A: Data-binding is used to bind or connect the data of the application with the Document Object Model.

9. Explain lifecycle hooks.
As soon as an Angular component is created, it enters a lifecycle. Using lifecycle hooks, we can trigger a specific time phase of this lifecycle. There are several lifecycle hooks, each triggering a specific time of the life cycle.

10. When is the ngOnChanges() lifecycle hook triggered?
 ngOnChanges() lifecycle hooks triggers whenever the value of any input property changes.

11. Is AngularJS and Angular?
A: No, Angular is the complete re-written version of AngularJS. While AngularJS uses JavaScript, Angular uses TypeScript. Angular offers feature such as services and directives while no such features are offered by AngularJS.

12. Explain Templates in Angular.
A template in Angular is nothing but a view that renders an Angular component's data or properties.

13. What is NgModule used for?
NgModule is used for declaring everything that we create in Angular and finally grouping them like a package in Java.


14. Define a Transpilation.
Transpilation is the process of converting TypeScript into JavaScript in Angular.

15. Which Angular lifecycle hook is called when 1) component's views and child views are initialized. 2) component's views and child views are checked?

1) ngAfterViewInit is called when the component's views and child views are initialized.

2) ngAfterViewChecked is called when component's views and child views are checked.

16. Differentiate between promise and observable.
A promise is executed immediately after creation while observable executes after the subscription starts. .then() is used in promise while observable has subscription and chaining. Moreover, observable can provide multiple values while promise can provide only one.

17. What is the purpose of the structural directive? Give an example.
A: The purpose of the structural directive is to change the structure of DOM. *ngIf and *ngFor are examples of structure directives.

18. Explain string interpolation.
A: Angular provides a special syntax for displaying the data of the component in the template using the template expressions within double curly braces.

19. Name the different types of directives in Angular.
A: Component directive, Structural directive, and Attribute directive.

20. How is Angular better than jQuery?
A: Many features are supported by Angular but not by jQuery. For example, powerful features such as RESTful API, deep linking routing, and form validations are supported by Angular but not by jQuery. Moreover, Angular is a full-fledged framework while jQuery is a JavaScript library.

21. Name the different types of filters supported by Angular.
A: There are several filters in Angular. These include json, data, filter, currency, limit, lowercase, uppercase, orderBy, and number.

22. Explain dependency injection.
A: Dependency injection in Angular is a software design pattern in which, instead of hard-coding objects in components, they are passed as dependencies.

23. How will you use animations in Angular?
A: To use animation in Angular, I will first import the Animate library, a special Angular library. Then, I will add a dependency i.e. ngAnimate in the application module.

That's all about the common Angular Framework Interview Questions for JavaScript and Web Developers. So, as mentioned earlier, Angular is a very popular web framework and it is in high demand. 

Clearing its interview can be tough, especially if you are inexperienced because Angular is huge. It has way too many concepts. But interviews are generally conducted around components, services, lifecycle hooks, NgModule, and directives. 

In this article, we listed 20+ Angular questions and most of them were related to the topics mentioned in the previous line. If you wish to clear the interview, go through the questions and try to research them as much as you can.

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