Popular Angular Interview Questions and Answers

If you are going to attend an interview in the technology field, you can expect questions about your education, work history, and certifications. However, it is also likely that you will hear technical questions during the interview. 

If you review important technical topics according to the position or field you are interested in before attending a technical interview, you can provide better answers.

Here are the most frequently asked Angular interview questions and answers. 🗣️👇

 

Most Frequently Asked Angular Interview Questions

1. What is Angular?

JavaScript framework is Angular, is used to develop single-page applications. It is free and open-source, allowing anyone to use Angular. 

Angular has a consistent structure. Additionally, it is highly scalable and very easy to maintain. It provides convenience by eliminating the need for developers to write code from scratch. Angular is written entirely in TypeScript. It uses the syntax of HTML to clearly express the components of applications. 

 

2. What is TypeScript?

TypeScript is an object-oriented, compiled programming language built on top of JavaScript. It is a superset of JavaScript designed to provide better tools at every scale. TypeScript makes JavaScript development more efficient. It helps in detecting errors earlier.

 

3. What are the features of Angular?

Angular has several features that stand out compared to other JavaScript frameworks. 

Some of these features are as follows:

 

1. Angular CLI: Angular provides support for command-line interface tools. These tools can be used to add and test components.
2. Animation Support: Angular allows the creation of high-performance and complex animation timelines with minimal code.
3. Cross-Platform Application Development: Angular can be used to create desktop applications for Linux, macOS, and Windows.
4. Code Generation: Angular can generate optimized code for JavaScript using templates. 
5. Templates: It allows the creation of UI views with simple and powerful template syntax.
6. Testing: Angular frequently allows unit testing.

 

4. What are the advantages of Angular?

• ✅ Ready-to-Use Features: Various features such as routing, state management, the rxjs library, and HTTP services come ready to use with Angular.
• ✅ Comprehensive Documentation: Angular offers documentation support to help developers better understand Angular.
• ✅ Angular CLI: The Angular Command Line Interface offers a set of useful tools for coding, making the developer's job easier. 
• ✅ Google Support: Google created Angular to use internally for their official websites and to solve issues in Google's internal systems. Google continuously updates and develops Angular. 
• ✅ Large Developer Community: Angular is highly popular among developers. Angular experts continuously contribute to Angular, share their programming experiences, discuss specific topics, and find ways to solve problems together.

 

5. What is the difference between Angular and AngularJS? 

AngularJS and Angular are often confused. However, there are significant differences between them. AngularJS uses JavaScript, while Angular uses TypeScript. AngularJS supports the MVC design pattern. Instead, Angular relies on components and directives. Angular supports dependency injection. AngularJS does not.

AngularJS does not have mobile support, whereas Angular does. AngularJS uses $routeprovider.When () for routing, whereas Angular uses @RouteConfig{(…)}. AngularJS is fast, and the development time is significantly reduced. However, with enhanced features, Angular is faster.

 

6. Can you create a backend application with Angular?

Yes, applications can be created on the backend using Angular Universal. Angular Universal provides better user experience and SEO results. Additionally, Angular Universal loads faster. 

 

7. What is data binding? 

✔️ Data binding means synchronizing the components that the user interacts with and the data. Data binding in Angular is an important concept that helps define the communication between a web page component and the DOM. Angular is known as a very powerful framework regarding data binding.

Data binding is mostly used in web pages that contain interactive components such as games, calculators, forms, and tutorials. In fact, data binding keeps the web page up to date. In Angular, data binding is achieved through components and template.

By using component templates, data can be bound between the model and the view. This way, changes within the components are reflected in the view of the template.

 

8. What are templates in Angular?

📍 Angular templates allow applications to define their user interface. HTML templates include Angular elements and attributes. Templates are created by using the HTML, CSS, and some special Angular features of components together.

 

 

9. What are directives in Angular?

Directives are attributes that allow users to write new HTML syntax specific to applications. Directives make HTML code more understandable and provide more functionality. 

Angular supports two types of directives: component directives and structural directives. 

 

• 1️⃣ Component directives are directives used in the templates of components. 

• 2️⃣ Structural directives are used to extend the functionalities of HTML structures (div, span, etc.).

 

10. What is AOT? 

AOT stands for Ahead of Time. AOT compilation is a compilation method used to enhance the performance of Angular applications. This method makes the execution of applications faster.

AOT compilation allows the application code to be transformed into compiled JavaScript code. This way, all the code necessary for the application to run is provided in a pre-compiled and optimized form. Thus, when the application is run, operations like code compilation and optimization are not required.

AOT compilation can be performed automatically by Angular CLI. The CLI generates the compiled JavaScript code of the application and serves this code as a single file. This makes the application load faster and run more efficiently.

 

11. What is dependency injection in Angular? 

Dependency injection is an application design model implemented by Angular that forms the core concepts of Angular. This feature is a fundamental aspect of the Angular framework and provides benefits in many ways.

Dependency injection allows a component to automatically receive the services or objects it needs from other components, instead of having them hard-coded within the component itself. This reduces dependencies between components and makes the application more modular.

Dependency injection also increases the testability of applications. For example, if the services a component needs are created directly within that component, testing that component becomes difficult. However, by using dependency injection, a fake version of the services the component needs can be injected during testing.

 

12. What are Expressions in Angular?

In Angular, "expressions" are structures used in HTML templates to display and process dynamic data.  Expressions in Angular are similar to JavaScript.  These expressions are used to bind application data to HTML.

📍 Example syntax: 

 

13. What are components in Angular?

Components are the fundamental building blocks of the user interface in an Angular application. Components contain the HTML templates, CSS styles, and JavaScript code that will be displayed in the user interface.

Each component is associated with a template and is a subset of directives. A typical Angular application consists of a root component called AppComponent, which then breaks down into other components forming a hierarchy.

In Angular, using and managing components is very easy. Thanks to the dependency injection feature of components, it becomes easier to communicate and transfer data between different components of the application.

 

14. What are pipes in Angular? 

Pipes are used to format and present expressions in a way that makes the output more readable for the user. They can be used in view templates, controllers, or services. Some pipes are as follows:

 

📆 Date Pipe: Used to format dates. 

🔠 Uppercase Pipe: Used to transform a string to uppercase. For example, the expression {{ 'merhaba' | uppercase }} will display as "MERHABA".

🔡 Lowercase Pipe: Used to transform a string to lowercase.

1️ Decimal Pipe: Used to format numbers. 

💲 Currency Pipe: Used to format currencies. 

 

15. What is Bootstrap? 

Bootstrap is a powerful toolkit. It is a collection of HTML, CSS, and JavaScript tools used to create responsive web pages and web applications.

To add Bootstrap to an Angular project, you need to install it in the project folder using NPM (Node Package Manager).

 

16. What are Template and Reactive forms?

➡️ Template forms are forms where all validations and controls are written in the template section of the code. The template is responsible for preparing, validating, controlling, and grouping the form.
 

The following command is used for template forms:

 

➡️ Reactive forms are an approach used to bind data between HTML form elements and Angular components and to manage form data. When managing form validations, properties and methods of the “AbstractControl” class are used to control the form state and determine when messages are displayed.
 

The following command is used to create a reactive form:

 

17. What kind of DOM does Angular implement? 

DOM (Document Object Model) treats an XML or HTML document as a tree structure where each node represents a part of the document.  Angular uses the normal DOM. This updates the entire tree structure of HTML tags until it reaches the data that needs to be updated.

 

18. What is string interpolation in Angular?

String interpolation in Angular refers to a special syntax that takes advantage of template expressions to display component data in templates. These template expressions are enclosed in double curly braces. Thus, the corresponding output is embedded into the HTML code. 

 

19. What is the Angular routing structure?

Angular Routing is a structure used in Angular applications to create Single Page Applications. 

 

20. How are cookies set and cleared in Angular?

To use cookies in Angular, you need to add a module named ngCookies angular-cookies.js to your project.

1️⃣ To set cookies: 

 

2️⃣ To get cookies:

 

3️⃣ To clear cookies:

 

21. What is Angular CLI and what does it do?

Angular CLI (Command Line Interface) is a tool used to create, test, and deploy Angular applications. Angular CLI provides Angular developers with a set of command-line tools, making it easier to create, configure, and manage Angular projects.

 

22. What is Angular layout?

Angular Layout is a library used in an Angular application to create the layout. This library provides various layout elements that can be used to enhance the visual design of the application.

 

23. What is Angular Change Detection?

Angular Change Detection is a feature of the Angular framework used to detect any changes in the application and reflect these changes in the display of components within the application.

 

24. How do you update Angular 12?

Before starting to update your Angular project, make sure you have the latest version of Angular CLI (Command Line Interface).  

Within your CLI, you can update a project with the following command:

 

25. What are the differences between Angular and jQuery?

The biggest difference between Angular and jQuery is that Angular is a framework, while jQuery is a JS library. However, both support DOM manipulation and animations. The differences between Angular and jQuery are as follows:

• 🆚 Angular has two-way data binding, whereas jQuery does not.
• 🆚 Angular provides support for RESTful APIs, while jQuery does not.
• 🆚 Angular has form validation, whereas jQuery does not.

 

26. What is a Decorator in Angular?

In Angular, "decorators" are special functions used to customize and configure classes and class properties. 

Decorators are a unique feature of the TypeScript language and are of great importance in Angular. In Angular, decorators can be applied to classes, class properties, methods, and even entire modules.

 

27. How to hide an HTML element in Angular?

To hide an HTML element with a click, the ng-hide directive is used along with the controller. 

View

Controller

 

28. What is the purpose of FormBuilder?

FormBuilder is a syntactic tool that speeds up the creation of FormControl, FormGroup, and FormArray objects. 

✅ It reduces the amount of standard code required to create complex forms.
✅ FormBuilder allows the easy creation of control methods.

 

To use FormBuilder, follow these steps:

1. Import the FormBuilder class into your project.
2. Inject FormBuilder
3. Create the form content.

To import FormBuilder into your project, you can use the following command in the TypeScript file:

 

29. What is a provider in Angular?

A provider contains instructions on how an application component, service, or other object can access or create these objects. In Angular, providers are used to access a component or service. Providers are usually defined when creating a service or adding a service to a component.

 

30. What is jQLite?

jQLite is a lightweight version of jQuery implemented by Angular that provides basic DOM functionality. It is a subset of jQuery and is known as jQuery lite. It comes included by default with Angular. 

 

31. What is Dependency Injection in Angular? 

Dependency Injection is a software design model where dependencies are passed into a component instead of being hard-coded within it. 

In Angular, Dependency Injection (DI) is a method of providing components or services with the dependencies they need. This is used when components and services depend on each other and is one of Angular's core principles.

 

32. What is bootstrapping in Angular?

Bootstrapping in Angular is the process responsible for starting up the Angular application. Bootstrapping is the fundamental step for the application to run. Angular supports both automatic and manual bootstrapping.

 

Angular Developer Career Opportunities

Angular, a JavaScript framework, is one of the in-demand skills in the IT sector. Some popular websites that use the Angular framework include Netflix, PayPal, The Guardian, Lego, JetBlue, Freelancer, Weather…

Angular has been one of the popular frameworks used for creating dynamic web pages for a long time. In fact, one of the main reasons for the popularity of JavaScript is Angular. 

Angular’s high application performance, cleaner code, reusability of code, easy updates, and cross-platform compatibility have increased its popularity and made it a sought-after skill.
 

 

Next Step

Before attending an Angular interview, first clarify all the basic concepts. Many of the questions asked in the interview test your fundamental knowledge of Angular. Secondly, practice! Don't just review the theory; apply Angular to your applications. The more you use Angular, the better you will understand its concepts and various uses.

We hope this article about Angular interview questions will help you. If you want to learn Angular and build a career, Angular Bootcamps can teach you a lot. Coderspace Bootcamps help you specialize in this area. If you want to enhance your software development skills, our Bootcamps, we recommend checking out.