Frontend Interview Questions and How To Answer Them Perfectly

Frontend development is one of the most in-demand skills in the tech industry. This means frontend developer jobs are available and frontend developers are highly sought after.

 If you’re looking to land a new frontend developer job, be it a remote frontend development job or onsite, or just want to make sure you can ace your next interview, learning how to answer frontend interview questions is a must.

You’ve probably heard that software engineering interviews are hard. You might even be convinced that they’re impossible to crack. But don’t worry, you’re not alone – many people feel this way. The key is to be prepared. And that’s where we come in. 

In this blog post, we’ll give you a rundown of the most common frontend interview questions and how to answer them perfectly.

 Let’s get started!

Before we get into the questions asked and how to answer them perfectly, let us discuss what frontend development is.

Frontend development refers to the activity of building and maintaining the graphical user interface (GUI) for a website, application, or other digital product. For easy comprehension, frontend development is the practice of converting data to a graphical interface for human use, usually via a web browser. frontend developers use web technologies such as HTML, CSS, and JavaScript to create user-friendly web pages and applications.

Frontend engineers are responsible for ensuring that the GUI is easy to use and looks great. They also need to make sure that it works well with the backend systems that power the product making sure it looks good on all devices. Frontend developers typically work in a team with backend developers, who are responsible for the server-side code.

To be a successful frontend developer, it is important to have a good understanding of both frontend languages (such as HTML, CSS, and JavaScript) and backend technologies (such as PHP, Ruby on Rails, and Node.js). It is also helpful to have some experience with design tools such as Photoshop and Illustrator. If you’re looking to become a frontend developer, there are many resources available online, including courses, tutorials, and articles. There are also many boot camps and coding schools that can give you the skills you need to succeed in this field.

When heading into a frontend interview, it’s important to be prepared for the types of questions you may be asked. They can generally be grouped into six categories: questions about your experience, practical questions, coding challenges, questions about your code, behavioural questions, and browser compatibility issues.

Questions about your experience will help the interviewer get to know you and understand your skillset. Practical questions may test your knowledge of specific technologies or ask you to solve problems using your coding skills. Coding challenges are usually more difficult, requiring you to write code on the spot to solve a complex problem, questions about your code may ask you to walk through a specific section of code or discuss how you would approach solving a particular type of problem, questions on browser compatibility issues will test your knowledge of how different browsers render HTML and CSS, questions on CSS and HTML will test your knowledge of the syntax and semantics of these two languages. questions on JavaScript will test your knowledge of the language’s core features, such as its event-handling model and its prototype-based inheritance. Lastly, questions on design principles will test your understanding of how to create user interfaces that are both effective and visually appealing. By being prepared for these types of questions, you will be able to showcase your skills, ace your frontend interview and land the job you want.

Having answered what frontend development is and also explained the technical and non-technical interview process, let us dive right into the technical interview questions to expect as a frontend developer and how to answer them correctly.

1. Questions about your experience

Talk about your most recent project and what you did on it (your contribution)

1. What are your strengths and weaknesses when it comes to frontend development?
2. How many frontend languages are you conversant with and how has it/ they helped you in projects.
3. Can you think of an example where you had to use JavaScript Promises or callbacks?
4. Can you briefly describe your roadmap to becoming a frontend developer? 
5. What frameworks do you use and what are the lifecycle hooks for those frameworks (sometimes it is about the framework they use as an organization) so ensure the frameworks you are conversant with are in tandem with the organization you are interviewing with.

2. Practical Questions

When interviewers ask frontend developers practical questions, they are looking to assess your technical skills and abilities. They want to know if you have the knowledge and experience to do the job and if you can communicate effectively. interviewers also use these questions to get a sense of your personality and how you would fit into the team. To impress your interviewer, it is important to be prepared for these questions and to answer them confidently. With a little practice, you will be able to demonstrate your skills and give the interviewers the impression that you are the right candidate for the job. 

Below are some practical questions you can expect. While this is not exhaustive, you can use this as a guide

1. What is the better approach to making an ajax call onkeyup or making the call after a complete phrase is entered in a search box?
2. How would you go about finding an element in the DOM by its ID or class name, and what are the potential problems with doing so?
3. What is the call, apply, and bind methods, why would you use bind()?
4. What’s the difference between inline and block-level elements, and how do you know which one to use when coding HTML markup?
5. How would you create a custom event in JavaScript, and what are some of the most common uses for them?
6. What’s the difference between a variable and a constant, and when should you use each one in your codebase?

If a question like “What is the call, apply, and bind methods, why would you use bind()?” comes up, here is a good way to answer it.

The bind method is used to create a bound function. A bound function is a function with a fixed context. The this keyword inside the function is bound to the object that was passed as the first argument to the bind method. The first argument to the bind method is also used as the first argument when the bound function is called. The bind method can be used with any function, not just methods. 

The apply and call methods can also be used to set the this keyword inside a function but they differ from the bind method in how they set the this keyword and in how they pass arguments to the function. The apply and call methods take an array of arguments whereas the bind method takes each argument separately. 

Apply and call are both functions that execute immediately, whereas bind creates a new function that can be executed at a later time. 

The apply method calls a function with a given this value, and arguments provided as an array (or an array-like object). 

The call() method calls a function with a given value and arguments provided individually. 

 Bind should be used if you want to create a bound copy of a function but you don’t want to invoke it immediately. Apply and call

Read how to Understand Call, Bind, and Apply methods here 

Don’t forget to elaborate and give actual examples and use cases. 

For a question on “Coding challenges”, this is a good way to answer it

When presented with a coding challenge, it can be tempting to immediately start typing away in an attempt to get the code working as quickly as possible. However, this is often not the best approach. Instead, it is important to take a step back and understand the question that is being asked. Rushing into coding without fully understanding the requirements can often lead to wasted time and frustration.

For other parts of the question that may seem unclear, it is important to ask for clarification before starting to code. Once you have a good understanding of what is required, you can then start working on a solution. It is often helpful to sketch out a rough plan of how you intend to approach the problem before starting to write any code. This can help to focus your thoughts and make the coding process more efficient.

Questions on coding challenges

1. How do you go about solving a problem like [x] ? ( be ready as this would be a practical session)
2. What is a call back function?
3. What is the difference between Synchronous and Asynchronous programming? 

NB: Be prepared to also solve algorithm questions

Here is one of the possible ways to answer the question “What is a callback function?”

There’s an adage that says “the best defence is a good offence.” That means when you are being attacked, it may be time to attack back. 

Callback functions allow us as programmers and developers of software systems the power we need to complete routine tasks quickly with ease!

In programming, a callback function is an argument passed into another routine that’s invoked when the corresponding action has been completed. Callback functions are often used in tandem with await statements to gate Call them without waiting for all of their output to finish typing out first!

Here’s a quick example from mdn web docs

Here ensure that you talk about your skill, your experience, how you learned them, and a project you used them in. 

They are checking how you apply your experience here. 

3. Questions about design principles

Whether you’re a graphic designer, web developer, or app builder, you’re bound to be asked about your design principles at some point. And while there’s no one-size-fits-all answer to this question, there are a few key things to keep in mind when responding.

First, it’s important to have a good understanding of the different typefaces and how they can be used effectively. Are they easy to read? Do they convey the right tone for your message? 

Second, colour is critical for any website or app interface – it should be used thoughtfully and deliberately to create the desired effect. Consider the colours you’re using. Is the colour scheme consistent across your website or app interface? Are the colours easy on the eyes and appropriate for your target audience? Finally, remember that good design is all about solving problems

Finally, think about the overall design of your site or app. Is it clean and organised? Do the elements work well together? If you can answer these questions confidently, you’ll be able to respond to any questions about design principles with ease.

Questions that you should expect to be asked about design principles can include;

1. What is your favourite typeface and why?
2. How do you choose colours for a website or app interface?”

4. Questions about browser compatibility issues

One of the most common questions developers get asked is about browser compatibility. With so many different browser options out there, it can be tough to keep up with which ones support new properties and features. Additionally, security is always a concern when it comes to browser usage. Here are some tips for how to answer questions about browser compatibility issues:

First, make sure you have a good understanding of browser support for the project you’re working on. This includes not only which browsers are supported, but also which versions of each browser.

Once you know which browsers need to be supported, research the latest developments for each one. This will help you stay up-to-date on new properties and features, as well as any security concerns.

Finally, be prepared to answer specific questions about browser compatibility. This may include questions about which browsers are supported, what features are available in each browser, or how to troubleshoot specific issues. By being knowledgeable and proactive, you can help ensure that your project runs smoothly on all compatible browsers.

An example of a question that can be asked about compatibility issues is;

What’s your take on browser support for new CSS properties/features? 

It is worthy to note that you will also be asked security questions so prepare for these too

5. Behavioural Questions 

Many employers will ask behavioural questions in an interview to get a better sense of who you are and how you would handle certain situations. While these questions can be difficult to answer, there are some general tips that you can follow to make sure that you give a well-rounded response.

First, when answering a question about your future goals, it is important to be realistic. Avoid making grandiose statements about where you see yourself in five years or ten years. Instead, focus on what steps you would like to take in the next year or two to progress in your career. This will show that you are ambitious but also realistic about what you can achieve.

Second, if an interviewer asks you for a reason why they should not hire you, this is not the time to be modest! You should use this opportunity to highlight your strengths and explain why you would be the perfect candidate for the job. For example, you could discuss your experience, skills, or qualifications that make you the ideal candidate. By doing this, you will turn a potentially negative question into a positive one.

By following these tips, you can ensure that you give confident and well-thought-out answers to behavioural questions in an interview

Behavioural questions

1. As a frontend engineer, where do you see yourself in the next five years 
2. Give us a reason why we should not hire you?

6. General tips for acing the interview process

Anyone seeking frontend developer jobs abroad or in Nigeria must be adequately prepared to be successful. This means having a well-written frontend development cover letter and resume, as well as a portfolio of projects that showcase your skills, knowledge of frontend development tools, and experience. Additionally, it can be helpful to seek out mentorship from more experienced developers to learn best practices and gain insights into the industry. By taking the time to prepare yourself professionally, you increase your chances of landing the frontend developer job you want.

Click here to read more on how to ace a frontend development interview 

We hope this guide helps prepare you for your upcoming frontend interview. Remember, practice makes perfect, so be sure to mock interviews with a friend or family member to help boost your confidence and go through these questions and answers as many times as possible before your big day. 

And finally, don’t forget to thank your interviewer for their time!

If you still have any questions or concerns, feel free to reach out to us for additional support. 

Good luck!