Top 25 Angular Interview Questions and Answers in 2022


Angular Interview Questions and Answers

Angular is one of the most popular web application development frameworks. It consists of several libraries that help developers build scalable web apps. This component-based framework also has several features that you should know before your interview.

This article is dedicated to helping you ace your Angular interview, so we will look at some of the questions you should expect. Employees and hiring managers are constantly looking for competitive employees; therefore, the earlier you anticipate these questions, the better off you are. Take a look at the following:

1. What Is Angular?

Angular is a client-side framework that divides codes into smaller bits of information and handles separation concerns for software developers. It is a component-based framework with a load of features that aid in developing scalable web applications. It is normally used when building applications that use complex logic.

2. Do You Think Angular Is Better Than Some Of The Existing Frameworks?

Angular has several features and capabilities that other existing frameworks do not enjoy. These features include state management, routing, RJXA library, and HTTP services that you have to source independently when using other frameworks. It also comes with a declarative User interface since it relies on HTML for UI rendering, which is easier to use than JavaScript. Lastly, Angular offers long-term Google support that most frameworks do not. Google announcing that it will support Angular for a long duration is evidence enough that it sees the future in it.

3. Define Aot Compilation

All angular applications come with components and templates that cannot be understood by the browser, making it necessary for all angular applications to be compiled before they are fed into the browser. There are two types of compilation in Angular: AOT or ahead-of-time compilation and JIT, which means just-in-time compilation. AOT Compilation means that applications compile as it builds, whereas JIT compiles the application during runtime.

Why Should We Hire You? 5 Best Answ...
Why Should We Hire You? 5 Best Answers

4. What Are The Advantages Of Using AOT Compilation?

AOT Compilation offers several advantages worth pursuing. The browser can load the executable code and render the application instantaneously since compilation is done before runtime. Also, it is easier to detect and correct errors as the application build, an advantage just-in-time compilation does not enjoy. Additionally, there are few ajax requests in AOT compilation since external HTML and CSS files are sent together with the application. Lastly, AOT compilation leads to better application security because it eliminates extra HTML files to be read.

5. Can You Mention The Differences Between Angular And Angularjs?

Angular and AngularJS differ in architecture, language, mobile support, expression syntax, and structure. Regarding architecture, Angular uses components, which are directives with a predefined template instead of controllers, while AngularJS utilizes a Model View Controller architecture, commonly known as MVC. The model is equipped with business logic, and the controller processes information and views. On language, AngularJS uses JavaScript while Angular relies on TypeScript language, a JavaScript superset. AngularJS does not offer mobile support on mobile support, while all the popular mobile browsers support Angular. Angular also offers a better structure than AngularJS, making maintaining code for bigger applications easy. Lastly, AngularJS requires the correct ng-directive for event binding while Angular only requires [ ] for property binding and ( ) for event binding.

6. What Are Modules In Angular?

A module is a location in Angular where components, directives, pipes, and services are grouped. Modules also determine whether directives and components can be utilized by other modules as they either export or hide them. There are two modules defined by the @NgModule decorator: root and feature modules. There is only one root module in Angular applications, whereas there can be limitless feature modules. The role of the root module is to import the browser module while the feature module imports the common module.

7. What Do You Understand By String Interpolation And Property Binding In Angular?

Data binding in Angular is divided into two parts, string interpolation, and property binding. Data binding allows communication between a component or model and its HTML template. This normally occurs in two ways, one-way or two-way binding. It is possible to insert data from a component into the HTML template in Angular. Changes directly reflect inside the HTML template for one-way binding and do not in two-way binding. On the other hand, string interpolation displays data ROM components using double curly braces.

8. Can You Differentiate Angular Expressions From Javascript Expressions?

The main difference between Angular and Java Expressions is that while Angular Expressions allow developers to write JavaScript in HTML, JavaScript expressions do not. JavaScript Expressions are also evaluated against global window objects, while angular expressions are evaluated against a local scope. This is because angular expressions normally display the message property of a component. Lastly, angular expressions do not allow the use of conditionals, loops, and exceptions.

9. Differentiate Observables From Promises

There are three main differences between observables and promises. While a promise emits a single value, an observable emits several values over a short duration. Promises are not lazy, while observables are lazy. They cannot be called until one subscribes to them. Lastly, a promise cannot be canceled, while an observable can be canceled through the unsubscribe () method. It has operators such as reduce, retry, retryWhen, filter, and forEach, among many more.

10. Angular Uses The Client-Side To Render All Its Applications. Can You Make It Render On The Server-Side?

Yes. Thanks to its amazing Angular Universal technology, I can easily make Angular render on the server-side. It comes with many advantages that web developers find useful. First, it empowers server-side rendered applications to load faster, given that rendered pages are delivered to the browser faster. It also allows first-time users to instantly he a view of the application, thus granting its user’s better user experience. Lastly, it ensures that content is visible in all search engines since many of them expect pages in plain HTML. In short, it offers better search engine optimization.

11. Explain What Directives Are In Angular

Angular has directives, which are classes in Angular declared with a @directive decorator. Each directive has its behavior and is capable of importation into different application components. Directives should be used for applications with several components that should have the same functionalities. When one creates a directive with the required functionality, they only need to import the directive to the components that need the functionality instead of adding the functionality individually to all the components. It, therefore, saves the developer time and effort.

12. Mention The Different Types Of Directives In Angular

There are three types of directives in Angular. The component directives make up the main class. They are using a @component decorator instead of @directive, which makes them special. They have a selector property, view, and stylesheet. The second type is the structural directives used to manipulate DOM elements. They come with a ‘*’ before them and can be applied to any DOM element. The last type of directive is the attribute directive which changes the look and behavior of a DOM element. They can be generated from the directory found in the angular application, manipulated, and applied to any DOM element.

13. What Do You Understand By Dependency Injection?

Angular uses dependency injection as one of its application design patterns. In this case, dependencies refer to the services in Angular that have functionality. A service’s functionality is often required by the different components and directives in the application. Angular, therefore, comes in handy by offering a smooth way of injecting these dependencies into the different components and directives by ensuring that all the dependencies ate injectable across every application component.

14. What Do You Know About The MVVM Architecture?

The MVVM Architecture stands for model, view, and view model architecture. The model carries the entity’s structure, i.e., the data of a given object. View refers to an application’s visual layer and thus shows all the data inside the model. It is, therefore, the HTML template of a component. The application’s abstract layer is the last part of the MVVM structure, ViewModel. It handles all the application’s logic and manages the data found in the model before displaying it in the view. Data binding connects the view and ViewModel in a two-way data binding method. The ViewModel notes any changes in the view and makes it reflect in the appropriate data contained in the model.

15. Can You Define Data Binding?

Data-binding plays an important role in bettering the browsing experience of users as it allows them to manipulate web page elements through the web browser easily. This phenomenon relies on dynamic HTML instead of complex scripting and programming. It is used in web pages with interactive components such as tutorials, games, calculators, and forms. It also supports incremental display and comes in handy whenever pages have large amounts of data.

Angular relies on the two-way binding, which makes changes made to the user interface on the corresponding model state.

16. What Are The Advantages Of Angular?

Angular has several advantages owing to its features and functionalities. It has several design patterns, such as directives and components that empower developers to create applications easily. It also has dependency injection, which makes handling interdependent components easier. Additionally, Angular has several generic advantages such as unit testing, data binding, superb responsiveness, and clean code, among many others. Lastly, Angular shapes application structuring owing to its MVC architecture. Its bi-directional data flow feature also comes in handy.

17. Mention The Technologies Used In Angular

Angular relies on several technologies, given that it is one of the most recent JavaScript frameworks by Google. These technologies are used to accomplish different tasks given this framework’s wide and increasing readability. They also give developers a better experience when using Angular to develop applications. One of the most popular is TypeScript, a JavaScript superscript. It allows developers to write JavaScript as a typed language and define their preferred types, thus promoting easier bug identification. Angular also uses RXJS, which empowers developers to handle asynchronous operations effectively.

18. Why Would You Advise A Developer To Shift To Angular?

There are several reasons developers should use Angular in their application development projects. This framework comes with an amazing collection of libraries, frameworks, and plugins that fastens the development process. Such developers will also have a good time developing applications. Angular also makes it easier to separate codes into modules which comes in handy in tasks such as data validation, routing, and HTTP communication. Lastly, Angular is built on TypeScript, empowering developers to come up with strongly typed codes that are later transpired to Java. Such codes are usually easy to read and maintain. They are also mostly error-free.

19. Angular Also Comes With Advantages. Mention Them

Having used Angular for quite some time now, I understand all the disadvantages this framework may have. It isn’t easy to achieve impressive SEO results in an Angular application without the right configuration, which is disadvantageous to content creators. This framework also comes with multiple features, which can be quite confusing. It may take time to know and learn how to use all of them in your application development projects. Lastly, Angular is mostly suitable for larger projects because it can significantly add weight to a JavaScript bundle. It is quite inefficient for small projects.

20. Differentiate Between Components And Modules In Angular

Components are the fundamental units of Angular’s user interface. They are made up of HTML, CSS, and JavaScript, which all make up different portions of the user interface. Only Angular can understand its components, given that they are custom HTML elements. It is worth noting that all components in Angular are isolated and brought together by it to build the user interface.

On the other hand, modules contain codes that touch on specific aspects of an application, such as HTTP validation and routing. Modules are created via the NgModule decorator.

21. Define Templates And Pipes In Angular

Angular has templates that are written using HTML. They are Angular-specific elements and attributes that can be mixed with the model and controller data to create a dynamic view when rendered. Pipes offer a means of manipulating dynamic data before being put into the templates. They can be used by the expressions, given that they are simple functions. Pipes can be used throughout the lifecycle of the application development once they have been declared and registered within the Angular framework.

22. Define The Different Types Of Bootstrapping

Angular has a bootstrapping feature used to start or initialize an Angular application. It is, therefore, basically getting the application to run. Like a variety of other systems, initializing Angular can either be done manually or automatically, which gives rise to manual and automatic bootstrapping.

Manual bootstrapping offers more control to developers when it comes to initializing the Angular application. They can choose when and how to use it. It also comes in handy during multitasking.

On the other hand, automatic bootstrapping is often used to add the ng-app directive to the Angular application’s root, empowering it to load a given module upon receiving the directive.

23. Mention Four Building Blocks Of Angular.

Angular has several building blocks. Some of the most common are the services which are made up of functions, values, and features that serve different roles, and the Angular router that interprets the URL into a client-generated view and experience. It is positioned so that Angular can instantly access the application view when a client clicks. Angular also has meta data in its classes that help the framework in class processing. They are often attached via decorators. Lastly, Angular greatly relies on dependency injection, allowing it to offer the right dependencies to new components.

24. Mention All The Types Of Angular Filters

There are nine types of Angular filters. These features come in handy in formatting the expression value before showing it to users. Filters are generally added to services, templates, directives, and controllers and can also be created depending on the requirements. Filters empower development teams to easily organize data, ensuring that only the right one is displayed. When used in expressions, filters are placed after the pipe symbol. The types of filters used in Angular are number, limit, uppercase, JSON, order by, lowercase, date, currency, and filter.

25. Define Routing In Angular

Routing is a response to the URL changes generated by adding or removing the application’s contents. It is complicated given that one must first intercept the request to prevent the browser from reloading before determining the exact content to remove and add. Lastly, the browser’s URL must be changed to communicate the exact page to the user.

Routing is normally quite difficult to implement, so Angular has a router targeting single-page applications. Routes are always defined with matching components before Angular takes over.

Conclusion

You don’t have to worry about your upcoming Angular Interview if you prepare well in advance. We have covered some commonly asked questions by hiring managers that should come in handy. Also, remember to be as confident as possible.

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