Angular Interview Questions and Answers

Are you a Angular Developer seeking a job in one of the top US MNCs? Or, are you a recruiter from a top US MNC looking for an excellent Angular Developer? In either case, you have landed on the right page.

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Angular is a framework that uses HTML and TypeScript to build scalable client applications. It’s an open-source JavaScript and component-based platform that's managed by Google. Angular helps to build essential, reliable, and convenient applications that are used in everyday life — social media, e-commerce, online banking, and healthcare.

Angular has many advantages that make it a popular framework to work with. Not only does it have a standard structure that makes work nearly effortless, but it's also reusable, readable, and unit-test friendly. Additionally, Angular's structure is constant. Developers can rebuild code from scratch, boosting their performance and making web development more efficient. Altogether, this makes it far easier for developers to create large applications and maintain them down the road.

If you’re looking to hire an Angular developer, then you might have some questions about Angular's core concepts and the questions you’ll need to ask during the interview. Though the interviewing process can feel daunting and drawn out, it’s best to prepare for the interview ahead of time can help by thinking about the best questions you can ask and what answers you should look for.

In this guide, we’ll go over some Angular core concepts, some of the Angular interview questions you might come across, appropriate answers, and explanations as to why the answers are the way they are.

Angular Core Concepts

What are the core concepts of the Angular framework? It has three:

  • Modules: The Angular framework relies on prebuilt modules, which are referred to as NgModules. They're marked with an @NgModule annotation in Angular’s framework. RouterModule, FormsModule, and Angular’s material design module are all common and popular modules of the Angular framework.
  • Components: Angular is a component-based framework. One component is based on the Typescript class and interacts with views.
  • Services: Services are the bit of code that serves particular purposes for applications. They're generally reusable and follow singular responsibility principles.

Basic Angular Interview Questions

Besides basic Angular-specific questions, you may also ask questions to get better insight into candidates' behavior, past situations they've dealt with, and their educational background. Questions you may want to use in an interview include:

  • Tell me about yourself, your experience in software development, and your education.
  • Explain why you’ve chosen this field.
  • What is your greatest strength? What is your greatest weakness?
  • How do you think others would describe you?
  • Tell me about a time you showed leadership skills.
  • Tell me about a time when you’ve faced challenges and difficulties and how you handled them.
  • Explain how you successfully finished a task under pressure.
  • Tell me about a time you made a mistake at work and how you approached the mistake.
  • What would you do if you didn’t have enough information and were unsure about how to move forward with a coding assignment?
  • Explain how you would handle a situation in which your coworkers didn’t do their part of a coding project on time.
  • Tell me how you would handle a coworker who asked you to review their work only to find out that it was full of bugs and defects.
  • Tell me about the college or university you went to. If you were self-taught, please explain how you taught yourself what you know.
  • Explain why you want to work for our company and how you can contribute to our company’s growth.

Navigating Angular Interview Questions

In the highly competitive and fast-paced industry that is tech, interviews can be stressful and anxiety-inducing for interviewers and interviewees alike. Before jumping into interviews, you'll want to comb through and review any resumes that have come your way. After you've shortlisted a few candidates that have caught your eye, it comes down to how you choose the right one.

The next step will most likely contain a phone or video interview. You'll want to conduct these interviews with all potential candidates, assessing their skills, educational background, and experience. The point of the initial interview will be to determine the type of person your candidates are and what drives their success.

As you dive into the first phone or video interview, there are a few things you'll want to keep an eye out for with your prospective candidates. First, observe their demeanor. Are they calm, cool, and collected? These traits may indicate that your prospective candidates are confident in their abilities. However, if your potential candidates seem too nervous, this might be a reflection of their skills and experience. While interviews can make anyone nervous, your prospective candidate shouldn't be nervous to the point of fumbling over themselves and making too many mistakes.

Another thing you'll want to look out for is if your prospective candidates seem passionate and eager about the position they're interviewing for. Eager candidates will likely want to make a lasting impression on you and your company, and if they're hired, they'll most likely remain engaged and passionate about their position. Someone who doesn't show passion about the position may become disengaged and uninterested in the job they're hired for.

You'll likely be conducting these interviews for around 15-30 minutes, as long as the prospective candidate isn't a total flop. Be sure to ask your candidates about their background, history, and questions that put their skills to the test, such as asking them to describe a time they were met with a challenge at a previous job and how they overcame it.

If you were wowed by any of your potential candidates, you'll want to proceed to a remote coding interview and/or assignment. It's very important that you test a potential employee’s abilities before moving on to the next part of the interview phase. These tests are usually performed via phone call, Skype, or Zoom, but they can also be given as homework. These assignments generally take a few hours to complete and will help you assess your candidate's skills.

The final stage is the actual interview. It’ll normally be held onsite unless this is a strictly remote-based opportunity. It’ll contain coding challenges that must be completed by the prospective candidates in front of you, other interviewers, and human resource employees. If the interview is for a remote position, these challenges can be completed remotely over video conference software.

Once you've completed all of these stages, you should know which candidate or candidates you want to bring onto your team. Just be sure that the candidates you offer jobs to are professional and align well with your company's values and vision.

Keep in mind the following traits when conducting interviews. Your prospective employees should show:

  • Excitement and positivity regarding the company
  • Honesty and authenticity
  • Clarity and precision on questions asked, specifically on questions regarding an employee's past employment ventures and Angular projects
  • Directness when completing whiteboard challenges, and walking you through their thought process
  • Ability to ask questions if unsure about something

Junior Angular Interview Questions

Junior or entry-level Angular devs typically have little to no experience working in an Angular environment. Questions for these potential hires are likely to be less intense, but they should still test their knowledge. They may look like this:

What Is Angular?

Angular is a JavaScript, TypeScript-based framework that's developed and managed by Google. It's open-source and provides developers with a powerful but easy way of creating and maintaining front-end web-based applications.  

It allows developers to express application components in a concise manner through HTML syntax.

What Is TypeScript used for?

TypeScript is a child of JavaScript that provides developers with great consistency. Because of its consistency and syntax, the code base is easier to understand and manage.

TypeScript code is compiled into JavaScript and can run effectively across all environments.

What Features Does Angular Have?

Angular has various features that make it a great tool for front-end developers. For example, Angular has accessibility applications that let developers create accessible applications through ARIA-enabled components and developer guides. It even has a built-in a11y test infrastructure to ensure that web applications are truly accessible to those with disabilities.

Some other notable features of the Angular framework include Angular CLI, Cross-Platform application development, and code splitting. It also includes built-in features like routing, state management, RxJS library, and HTTP.

What Are Modules?

Modules, or NgModules, are fundamental building blocks of an Angular application. These modules are organized code blocks that have their own particular capabilities and a specific application domain or workflow. Angular applications must have at least one module, which is the root module.

What Are Components?

In Angular, components are used to control one or several views. Views typically control one specific screen section, and a component can control that view for you. Components house application logic which is defined in a class. The class, along with an API of methods and properties, is then responsible for interacting with the view.

What Are Pipes?

Pipes, or parameters passed to a pipe, are categorized in two ways: built-in pipes and custom pipes. Built-in pipes are further classified into two additional types, namely, parameterized pipes and chaining pipes. As a whole, pipes are used to transfer raw data into required formats. This happens before the application is sent to end-users.

What Are Services?

The term ‘service’ is a broad one — essentially, a service can range in its functionality from being a value with a function to a feature. Simply put, services are classes that have well-defined functions.

What Is Data Binding? How Does Angular Use It?

Data binding is used to manipulate the elements of webpages using a web browser, typically through dynamic pieces of HTML. Data binding requires no complicated programming or scripting and is typically used on interactive web pages with forms, tutorials, and games.  

When referring to Angular, this framework uses two-way binding, which means that changes that are made to the user interface are then shown in the equivalent model state. When changes are then made to the model state, they are shown in the user interface, enabling Angular to connect the DOM and Model data via a controller.

What Are Single Page Applications?

Single page applications (SPAs) are a technology that allows one page, index.HTML, to be managed. SPAs allow users to continuously manage these pages despite URLs changing. When compared to traditional web technology, SPAs are easy and quick to build and use.

What Are Filters?

In Angular, filters are a feature that is used to format expressions and reveal them to users and are used in controllers, view templates, and services.

Date, filter, Json, limitTo, and lowercase are all types of filters with varying functions. For example, the date filter is used to format dates to specific formats, and Json formats an object to a JSON string.  

Additionally, there is a filter that selects a subset of items from an array.

What Are the Differences Between Angular and AngularJS?

There are several important differences between Angular and AngularJS. For starters, Angular is written in TypeScript, whereas AngularJS is written in JavaScript. Angular’s architecture uses directives, and AngularJS supports the MVC design (in other words, the model-view-controller design).

There are a few other notable differences between their mobile support, dependency injection, routing, and management areas, too.

What Are Decorators in Angular?

Decorators are design functions or patterns that help developers define how Angular features operate. Developers can use decorators to modify classes, filters, and services. There are four decorators that Angular supports using, including class decorators, method decorators, property decorators, and parameter decorators.

What Are Directives in Angular?

In Angular, there are three directives: component directives, attribute directives, and structural directives. These directives allow developers to create new HTML syntax for specific applications. Directives work with compilers to execute whatever is found in the DOM.  

What Is an AOT Compilation?

AOT compilers, or ahead-of-time compilers, translate code from HTML and Typescript into JavaScript. It’s used during build phases before the code is downloaded and used by the browser.

AOT compilation is very advantageous. In fact, it allows for better security, fast detection of template errors, and fewer asynchronous requirements.  

What Is a Framework, and Why Are They Important?

A framework is a program that allows software engineers and developers to create web applications through written code. Frameworks provide developers with a structure that has everything they would need to build a simple front-end application, such as support, guides, templates, and more.

What Is a Client-Side Framework?

A client-side framework is a JavaScript library that operates within a Web browser and allows developers to build their applications in a way that is displayed on the client or end-user device, including visuals such as text, images, the user interface, and more. Angular was introduced as a client-side framework to provide developers with an easier way to divide code into components and allow code to run faster, unlike when they’re carried out in frameworks such as VanillaJS and jQuery.

What Are Some Advantages of Using Angular?

Angular has a few advantages that make it a popular choice when compared to competing frameworks. These advantages include built-in features such as HTTP, state management, routing, declarative user interfaces that make Angular easier to use, and long-term support from Google, which developed and manages Angular.

What Are Some Disadvantages of Using Angular?

It can be difficult to learn Angular, as it’s a complicated framework, and dynamic applications may not always perform the best. In addition, SPAs that are more complicated can produce lag due to their size. However, these disadvantages don’t compare to the advantages that Angular provides its developers, and the benefits of this framework outweigh the drawbacks.

Senior Angular Interview Questions Examples

If you're trying to fill a position for an advanced or senior-level Angular developer, the questions you will need to ask during interviews are broader and more challenging. A senior Angular dev should know everything an entry-level dev knows and then some.

Here are some questions you can pose to a senior Angular developer:

What Is Bootstrapping?

Both manual and automatic bootstrapping are supported in Angular environments. Both provide developers with a powerful toolkit for their arsenal that gives them access to various HTML, CSS, and JavaScript tools. These tools allow developers to create, build, and manage responsive websites and applications.

Angular has two ways to embed bootstrap: via CDN, which is the Content Delivery Network that allows you to load JavaScript and CSS files from a remote environment into Angular’s servers, and via NPM, which is the Node Package Manager which allows bootstrap to be installed through a project folder.

What Is the MVVM Architecture? Explain.

The MVVM architecture consists of three parts that help reduce tight coupling in components. The three parts that make up the MVVM architecture include the model, the view, and the viewmodel.

The model is responsible for model classes, data sources stored locally and remotely, and the repository. The view is the visual layer of the MVVM architecture and is where the UI code resides. View transfers user actions to the ViewModel, which is the abstract layer that bridges the gap between View and ViewModel.

What Is the Digest Cycle Process?

In Angular, the digest cycle is a process to check and track changes that occur in the watch variable value, usually through monitoring the watch list. Digest cycles compare the present scope model values to the past versions.

In RxJS, What Does Subscribing Mean?

Reactive Extensions for JavaScript (RxJS) is a library that enables users to access and use observables in JavaScript projects. This allows programmers to conduct reactive programming. With Angular in particular, RxJS allows developers to create asynchronous operations.

What Is REST?

REST means Representational State Transfer and is an API that operates when HTTP requests it to. Once requested, the URL will then direct the data that has been processed, and the HTTP will be able to identify the respective operation which the data will be required to perform. When an API follows the REST method, they are known as the RESTful APIs.

How Are Directives Created Through CLI?

There are specific steps that must be performed to create directives through CLI.

First, you’ll need to start a new project using the following command: ‘ng new [application-name]’

Then, change the directory into a new directory, using the command: ‘cd [application-name]’

Once a new directory has been created and changed, a new directive should be made with the following command: ‘ng generate directive [path-to-directives/my-directive]’

And there you have it, you’ve used a CLI to create a directive.

What Is Schematic?

Schematics are code generators that are based on templates and used for complicated logic, typically so that software projects can be transformed by creating or manipulating codes.

Explain the Differences Between Angular Expressions and JavaScript Expressions

The main difference between Angular and JavaScript expressions is that Angular allows you to write JavaScript in HTML, but JavaScript does not allow that. In addition, expressions written in Angular are locally scoped, whereas JavaScript expressions are scoped with global window objects.

Common Angular Developer Practical Questions

Some practical questions that an Angular Developer may face include questions regarding the Angular framework, how it’s used, and more. You may also be required to solve some Angular challenges and problems. Questions may include:

  • What is Angular?
  • What is your experience working with Angular?
  • Explain when you’ve had a challenge with Angular and how you solved it.
  • What is AngularJS?
  • What is a framework?
  • What is Angular CLI?
  • What are template expressions?
  • What are template statements?
  • How can you read the full response?
  • What are custom elements?
  • What are router imports?
  • What is Angular animation?
  • How do you prevent automatic sanitization?
  • Explain how you would share data between components in Angular.

Giving Angular Developer Challenges

Challenges are given to software developers to ensure that they meet the right qualifications, experience, and education to be effective members of your team. One challenge that you could give an Angular developer is to implement a subset of an Angular UI library.

The library must be supportive of themes and provide users with a default. Clients should be able to create their own custom themes and override ones that have already been created.

To further strengthen this challenge, a demo application should be created. The demo should be able to show the features, usage documentation, and sample code of each component.

When designing, consider implementing the following:

  • Buttons
  • Input text
  • Input numbers
  • Select input
  • Autocomplete

The challenge should also call for the developer to divide code into smaller bits of information and push errors to the child promises to determine how well the developer actually understands the Angular environment.

Ask The Right Questions When Hiring Angular Developers

If you’re looking to hire an Angular expert but are unsure of how to find the perfect fit, reach out to us at Revelo. We’re a tech-based marketplace dedicated to helping businesses meet their next tech expert. You’ll get your choice from a pre-vetted list of the top-tier talent in Latin America, and we’ll handle the rest, including the hiring process and payroll.

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