Top 15 Angular Interview Questions and Answers

Written By Vikash Kumar

Modern software development industries are looking for skilled and highly educated developers who are aware of various demanding frameworks, especially JavaScript. And among all the popular JavaScript frameworks, Angular is one of the most demanding platforms in the market today.

Angular is quite vast and difficult to navigate. Consequently, interview questions based on the Angular framework can be tough, as it is laborious to get familiarized with each part of it.

In this post, I will guide you through both basic and advanced Angular interview questions that you can expect if you have applied for a post as an Angular developer. So without any further delay, let’s proceed!

Top 15 Angular Interview Questions and Answers

Q-1. What Is Angular?

Angular is an open-source and free JavaScript framework created by Google in 2016. It allows you to build modern web and mobile applications by implementing various web technologies such as HTML, CSS, and JavaScript.

The primary programming language used by Angular is TypeScript. Basically, it is an open-source front-end framework suitable for creating enterprise Angular applications, as it allows developers to reuse its code and is easily maintainable.

Q-2. What Are the Various Types of Technologies Used in Angular?

Angular is a free and open-source JavaScript framework that is highly preferred by web developers. The popularity comes from the use of several technologies to perform specific tasks easily. Angular allows for a great experience while building applications. It uses TypeScript, which is known as a superscript of JavaScript.

Q-3. What Are the Advantages of Angular?

The advantages of the Angular framework are:

  • Follows MVC architecture. MVC stands for Model-View-Controller, which is known as one of the best advantages of Angular. The Model is responsible for managing all the application data and the View manages the data display. The Model is said to be the lowest level of the pattern for maintaining data, while the Controller is a bridge between the View and Model layers.
  • Dependency injection. The dependency injection of Angular makes the process of application development easy for web developers. It is used to fulfill these dependencies and allows you to divide the task among different services. This is the main reason why developers prefer working with Angular development.
  • Two-way data binding. One of the leading advantages of Angular is its two-way data binding technique, which helps you to reduce the development time. The View layer represents the Model layer and remains in ideal synchronization. This way, users can see the changes in the View automatically when you modify anything in the Model.
  • Allows you to add custom directives. We can use directives in Angular to change DOM element behavior for which we need to use the directive name as an attribute to the DOM element.
  • Support RESTful services. The RESTful functionality in Angular is used to create APIs for a web-based application. It is provided in the ngResource module where it's separately distributed from the core AngularJS framework. These RESTful services are highly-scalable and maintainable.
  • Trivial code generation. Trivial code generation in Angular is a process of using specific tools to create metadata and get usable code output. This process allows you to reap all the benefits of handwritten code.
  • Validations are supported. Angular runs validation, generates a list of validation errors, and displays the results. Through this, you can improve the data quality by validating user input from the UI.
  • Support static and angular templates. Angular allows you to use TypeScript and editor tools so that you can statically analyze the components. Further, editors provide autocompletion feedback and detect which type of template is being used.
  • Build CLI commands visually. We can use the Angular CLI command line interface tool to initialize, develop, and maintain the angular apps directly from the command shell.
  • Offers excellent features like animation, event handlers, and much more. Angular can create high-performance, complex choreographies and animation timelines without much effort, and generate intuitive API with minimal coding. It also configures an event handler for the target event where it executes the template statement and performs an action in response to the event.

Q-4. What Are the Main Features of Angular?

The top features of Angular are:

  • Cross-platform app development. Angular allows you to build excellent desktop-installed applications for Windows, Mac, and Linux using the modern web platform and deliver app-like experiences. You can also build mobile applications with strategies from NativeScript, Cordova, and Ionic.
  • Code splitting. In Angular, code splitting is achieved by producing lazy-loaded modules, which deliver automatic code-splitting so that users can load the required code and render the view they request. To ensure that a module is lazy-loaded and divided into its own JavaScript chunk, don't forget to create a lazy-loaded route.
  • Animation support. Angular animations are built in a way that allows you to create high-performance and complex choreographies with little code, using the Angular intuitive API. The feature of Angular animation is built using the standard web animations API and runs on native browsers that support it.
  • Angular CLI. Angular CLI is a unique tool that allows developers to build, maintain, and initialize Angular applications from a command shell. Without Angular CLI, you need to invest a lot of effort while setting up an Angular app from the beginning. Not only this, but you also have to add a package definition file, such as package.JSON, and some other configuration files.
  • Declarative UI. The Angular framework uses the HTML language to define the application UI—when compared to JavaScript, this is a less complex option. As a declarative platform, you don't have to spend your time maintaining program flows and deciding what loads first and what does not.
  • Accessibility applications. Accessibility applications in Angular is a way of designing an app so that it can be accessible by those with a disability. Angular has the ability to build an app with good accessibility. It also uses attribute binding for ARIA attributes.
  • CDK and Angular Material. The CDK is a standalone package that implements common interaction patterns and builds awesome components for the web. It is used for projects that need to reap the advantages of Angular Material without adopting the Material Design visual language, and represent an abstraction of the core functionalities without styling specific to Material Design.
  • Differential loading. Differential loading in Angular development means sending fresh code to newer browsers and stable legacy code to legacy browsers, which helps you to translate two things: modern syntax and polyfills.
  • High speed and optimum performance. The lazy-loading feature that comes with Angular development helps to boost the application's performance and allows modules to be loaded only when they are required, so that files are not loaded repeatedly.

Q-5. What Are the Important Fundamentals of Angular?

Angular has numerous features that make it one of the most popular and useful frameworks compared to other front-end frameworks. These features of Angular are:

  • Component. The Angular components are known as the basic UI building blocks that belong to a NgModule and make themselves available for other components. An application developed using the component capabilities contains a tree of Angular components associated with a template.
  • Angular elements. Angular elements are Angular components known as web components, which is a web standard for identifying new elements based on HTML in a framework-agnostic way.
  • Directives. Angular directives are classes that add more behavior to elements when it comes to Angular applications. Using the built-in directives of Angular, you can manage forms, lists, styles, and everything else that users see.
  • Native mobile development. Angular also supports native mobile development and allows you to build amazing native applications by implementing strategies from Cordova, Ionic, or NativeScript.
  • Module. The angular module defines an application and has its own modularity system known as NgModules. Basically, it is a container for the application controllers that belong to a module.
  • Dependency injection. Angular dependencies are objects that a class requires to perform its function in the application. And dependency injection can be referred to as a design pattern where the class requests dependencies from external sources instead of creating them. This boosts the flexibility and modularity of your applications.
  • Templates. In simple words, a template is an HTML form that tells Angular how to render a component and defines its host view. It allows you to modify and hide entire UI sections as a unit.
  • Navigation or routing. Angular Router allows you to navigate from one view to the next when the user performs application tasks.
  • Data bindings. The system of data binding in Angular allows your application's components to share data with other components and update values between the child and parent components.
  • Application bootstrapping. Bootstrapping in Angular is a process of loading the index.html page, app-level module, and app-level component.
  • Services. Angular services are objects that are instantiated once during the lifetime of an application and increase the modularity and reusability to make your component lean and efficient. It is a broad category having a value, function, or feature that an app requires.

Q-6. What Is Data Binding in Angular?

Data binding is one of the most effective features of Angular development; it assembles a connection between application UI and displays the information.

The defining process of interactive software products is made simple because you're not required to worry about data pulling or pushing between the template and component. If the binding delivers proper notifications and is configured in the right way, the data value is modified and the elements that are bound to the data are affected automatically.

Two-way data binding, string interpolation, property binding, and event binding are the types of data binding that come with Angular development.

Q-7. What Is DOM?

DOM stands for Document Object Model and is liable for illustrating the web page content and modifications done in the application's architecture. All the objects included in it are managed in the form of a tree so that they can be easily accessed, modified, and manipulated using the APIs. You can use Angular directives to bind the application data to the attributes of HTML DOM elements.

Q-8. What Is the Difference Between Angular and AngularJS?

To better see the differences between Angular and AngularJS, I have included a comparative chart:

Parameters Angular AngularJS
Architecture Angular uses directives and components. AngularJS follows the MVC architecture.
Support Active support and frequent updates are made. No support and no new updates.
Speed Faster because of the updated features. Slower because of the lack of updates.
Mobile support Mobile support is available. No mobile support is provided.
Structure A simplified structure that can be easily maintained. Less manageable as it has a basic version that is easy to maintain.
Language TypeScript JavaScript

Q-9. Explain the MVVM Architecture

The MVVM architecture plays an important role in avoiding tight coupling amongst the components. There are three main parts included in this architecture:

  • Model. The Model consists of an entity structure that has business logic, including repository, model classes, and local and remote data sources. In short, it represents the business logic and data of a specific application.
  • View. The View is the app’s visual layer that includes the UI code. It sends the users’ actions to the ViewModel.
  • ViewModel. The ViewModel abstract layer is the bridge between the View and the Model. Both are linked via data binding and make all the necessary changes to the Model.

Q-10. What Are Directives in Angular?

Directives are attributes that allow users to write new HTML syntax based on their applications. Its syntax is executed when the Angular compiler confronts them in the DOM. Angular majorly supports structural directives, attribute directives, and component directives.

Q-11. What Is Angular CLI?

The angular command-line interface (CLI) tool allows you to build, maintain, and initialize Angular applications from a command shell. Angular supports CLI tools to allow developers to add components, perform testing, and many other such operations, helping to make the Angular development workflow much easier and faster. Angular CLI also helps save time required to install essential dependencies.

Q-12. Explain Dependency Injection

In Angular, dependency injection is a software design convention in which a class requests dependencies from external sources without creating them. It allows Angular to improve the flexibility and modularity of the application, as it uses design patterns to fulfill these dependencies and divides tasks among different services.

We can say that dependency injection is integrated into the Angular framework so that the clients are not required to create dependent objects—rather, they will be created by the injector.

The Angular injector is responsible for building new components, solving dependencies, and providing them to other components who need it. Fundamentally, it is a service having a functionality that is required by various directives and components in an application.

Q-13. Explain Angular Authentication and Authorization

Forevery system concerning security, authentication and authorization are very important processes in the system. This is no different with Angular.

The user credentials are given to an authenticated API that is available on the server.  Authentication allows the user to access some resources in the system. When your application authenticates the user and receives a token from Auth0 for access, only then is the user allowed to access the token to your API as a credential.

Q-14. What Are HTTP Interceptors?

Interceptor is a trendy term for a function that accepts requests before processing them to the server. If you want to pre-process multiple types of requests in the same way, then you can make use of interceptors. For instance, you need to set the authorization header token for each request that is received by the system as shown below:

Q-15. What Is Server-Side Rendering in Angular?

Sometimes, if you have a large application with rich features and a huge bundle size, the loading speed of the page is automatically lessened as it has to download all the files and then execute them.

To overcome this issue, you can use server-side rendering to send a fully rendered page and then let the JavaScript code take over any ensuing interactions from the user. In short, the browser executes an Angular application and JavaScript endures all the interactions held among the users.

Knowledge Makes Things Simpler

As I mentioned in the introduction, Angular is quite vast and difficult to navigate. This makes interview questions appear complex and daunting. However, as they say, knowledge is power. Knowledge makes things simpler.

The guide I offered you should help you to crack your Angular interview and turn your programming into your profession. The topics I covered here are all part of preparing for an interview and are the most frequently asked questions by recruiters while hiring Angular developers.

Apart from this question bank, you'll find numerous other Angular interview questions, but don't forget to also go through the soft skills required for developers if you really want to crack the interview in the first go.

Have a question stuck in your mind? Feel free to ask me in the comment section below, and I will get back to you soon.