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Angular Interview Questions

What are the most commonly asked Angular Interview Questions? Prepare for your interview by learning the most commonly asked Angular Interview Questions.

Submitting your resume is just the first step in growing your career with Angular Jobs. Employers are looking for someone that they are confident can provide the required value in the form of skills. That’s why, before accepting you for a role, they do their best to test your skills through different means.

Are you interviewing for Angular Jobs? Does your company use Angular and want it to be part of the interview process? Whether you’re a developer or a hiring manager, it’s important that you have a good understanding of the technology.

Prepare for success by making sure you’re familiar with the most common Angular interview questions.

Preparing for Angular Interview Questions

Through an interview, a hiring manager will attempt to gain insights on your skill level in the Angular framework. Developers should learn these commonly asked Angular interview questions to improve their marketability for Angular Jobs. 

Additionally, hiring managers and recruiters benefit from becoming familiar with these questions by better evaluating new applicants and potential candidates for their Angular Jobs.

Many companies utilize online testing platforms, but, even they continue to rely on the formal interview process prior to making any hiring decisions.

If you want to be successful at a company that is using Angular, whether as a developer, a manager, or even a recruiter, then you need to prepare yourself by understanding the top Angular interview questions.

Today, we’re going to focus on preparing you for those interviews. We’ve researched the most common interview questions. We’ll start with some of the most basic Angular interview questions, and we’ll also introduce some more advanced level concepts of the framework.

Most Common Angular Interview Questions

What is the difference between Angular and AngularJS?

  • AngularJS was the first public release of this framework.
  • Angular is based on TypeScript, AngularJS is JavaScript. 
  • AngularJS utilizes “scope” and “controllers” while Angular replaces those with hierarchical components.
  • It’s very important to note that AngularJS is not compatible with Angular. 
  • Many breaking changes are introduced in each major version release of Angular.
  • Angular is more modular than AngularJS, improving speed. 
  • Angular introduces a CLI that enables scaffolding, which makes development faster.

What is Angular and why do we need it?

Angular is a framework that is based on Typescript, a superset of JavaScript. The main reason behind its development is to help us create scalable applications that are rendered in the browser.

Some of its most noticeable features include the Ivy rendering engine, Service worker support, Angular elements, and AOT (Ahead-of-time) compilation.

It can be a great choice for designing Single Page Applications (SPA). That’s why the tech giant Google and major enterprises use it for major projects. Google has supported its development since the beginning, spending millions of dollars per year on the Angular team responsible for managing the project.

List Angular template type-checking modes

Basic Mode

Basic Mode should be preferred for live projects. Because it can quickly validate only top-level expressions.

Full Mode

Full Mode thoroughly validates Angular templates. So, it is more suitable in the development environment.

Strict Mode

Strict Mode was recently added in Angular 9 to work closely with the latest Ivy rendering engine. You should make sure to use this mode when starting the development of a new Angular app.

What are the differences between Angular components and templates?

Angular renders data inside HTML designs after collecting it from the controller and model. These HTML designs are then used to display the output on the user’s screen.

Here, the component works as a controller, which means that it is the one who gets data from the model and then transfers it to the view. While the actual HTML output is represented by an Angular template.

Explain the difference between Interpolation and Template Expressions

Through interpolation, you can easily embed dynamic content inside HTML tags and attributes. The dynamic content is generated or calculated with the help of template expressions while it is enclosed inside a set of double curly braces {{ }}. These curly braces are also known as the delimiter for interpolation.

In simple words, a template expression is nothing but a small computation that is carried out inside interpolation.

Briefly explain the Angular Component Class

In Angular, the Component Class retrieves data from a data store, the model, and then renders it inside the HTML user interface template. This is the similar to a controller in MVC architecture that controls the way how data moves from model to view.

What are the benefits of data binding?

Data binding is a very common concept among popular JavaScript front-end design frameworks. Through data binding, the components of our application can easily interact with the DOM. It helps you create interactive apps where you don’t have to spend any time figuring out how to push or pull data between components and templates.

What are Angular Pipes?

Pipes in Angular were formerly known as filters in AngularJS.

Pipes help us validate the data before displaying it to the user. Most of the time, it is used to transform existing expression value into a required format. Pipes can be easily attached to a controller, service, template or directive.

There are over a dozen frequently used pipes included with Angular. Custom pipes can also be created for specific use cases.

How are events managed in Angular?

Angular enables control over handling events according to our specific requirements. All of this is possible due to the flexibility of Angular event binding.

The syntax for bind events to an element includes removing the “on” from the standard DOM event and adding parentheses. For example, 

<button onClick="myFunction()"> in AngularJS

becomes 

<button (click)="myFunction()"> in Angular.

How can we test Angular applications?

There are several tools available that help us perform unit tests on our Angular based web apps. These are the most popular ones.

  • Mocha
  • Karma
  • Browserify
  • Angular Mocks
  • Sion

To succeed in your interview, be prepared to talk about how you’ve written tests in the past.

How is the lazy loading technique used in Angular?

Lazy loading is a popular concept in software development where the basic idea is to only load things when needed. In Angular, it is used to asynchronously load JavaScript components and modules. This, in turn, boosts the performance of our overall application.

New in Angular 9: In prior versions, you could lazy load modules. Since version 9 you can now use lazy loading with components.

Thanks to Kristoffer Lindström from the Angular Developers group for recommending this question.

Angular Interview Questions About Directives

What do you know about Angular directives?

Directives are functions executed by the Angular compiler.

Directives provide us the ability to change the DOM on the fly. It makes use of decorators to update existing JavaScript classes. You can add directives inside HTML tags, just like the attributes.

Directives that include an HTML template are known as components.

Angular is packed with three types of directives, that are as follow:

What are Structural Directives?

Structural Directives make changes to the DOM by adding and removing HTML elements.

What are Attribute Directives?

Attribute Directives update existing elements to change their appearance or behavior.

What are Component Directives?

Component Directives contain a template to be rendered and are the most common type of directive.

Angular Interview Questions About Decorators

Which items can decorators be applied to in Angular?

  • Classes
  • Methods
  • Accessors
  • Properties
  • Calling parameters

Thanks to Dwight Spencer from the Angular Developers group for recommending this question.

What is the difference between Annotations and Decorators?

Decorators are not specific to Angular, they are a feature of TypeScript. Annotations are a feature of Angular, not TypeScript.

Both annotations and decorators have the same purpose, which is to compile the @ symbol. But, they both work in a completely different way to achieve their objective.

Basically, a decorator is a function that can modify a decorated object passed to it. In other words, a decorator has the ability to change a class without editing its source code.

While on the other hand, the purpose of annotations is to create an annotation array. It uses the Reflect Metadata library and works as the only metadata set available in class.

Expert Knowledge of Angular Interview Questions

Congrats! You made it to the end. You should now feel more prepared for your next interview.

Are you interested in more expert level questions? Do you want to know how to evaluate Angular Experts? Let me know, my email is below.

Send me an email and let me know what you think! Did you like these Angular Interview Questions? Which questions should be added?

Thanks,
Brian
brian@angularjobs.com

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