Image for 30 Best Interview Questions For JavaScript Developers

24 May 2023

30 Exceptional JavaScript Developer Interview Questions

No one can deny the popularity of the JavaScript programming language. With 98% of websites using this technology as their go-to client-side language, it’s safe to say that all organizations should at least consider the possibility of hiring IT professionals who specialize in this tech stack. But recruiting specialized developers, even for a programming language this popular, requires a prior understanding of what skills and expert knowledge all candidates should have. That’s why this article is dedicated not only to the ABC of JavaScript development but also to the best interview questions for professionals proficient in one of the most popular programming languages out there. Keep reading to learn what to ask before you hire JavaScript developers for your projects! 

What Is JavaScript Development?

Originally developed by Netscape in 1995, JavaScript is a long-standing extremely popular programming language known above all for its crucial role in modern web development. Thanks to the high interactivity of this tech stack, it has become an essential tool for creating dynamic and interactive websites. JavaScript allows developers to create animations, form validation, navigation menus, and other dynamic features that can make your websites more engaging and user-friendly. Plus, it can also be used for server-side scripting, alongside technologies like Node.js, giving specialized IT professionals the power to build full-stack applications using a single language. Today, we completely depend on it for anything having to do with interactive web page elements. If you disable JavaScript, you’ll soon realize most of your favorite websites won’t load or display as they should.  

Why Should Your Company Choose To Hire JavaScript Developers? 

Beyond the very real necessity of using JavaScript for your website’s interactive elements, the decision to hire JavaScript developers can bring you multiple benefits. To start, your organization will actually count on the support of someone with specialized expertise in this technology, and experience making all functions work properly. JavaScript developers can optimize your website’s performance by implementing features like lazy loading, caching, and code minification - a good number of improvements that require expert knowledge and experience testing what works and what doesn’t. Moreover, with the use of JavaScript for server-side tasks when paired with other tech stacks, your company could gain access to fulls-tack development capabilities after you hire JavaScript developers. This can help you save time, money, and resources over time, and will certainly contribute to the success of your web development projects. 

30 Best Interview Questions For JavaScript Developers

What is JavaScript? How does it differ from other programming languages?

What are the data types in JavaScript?

Explain the concept of hoisting in JavaScript.

What is the difference between undefined and null in JavaScript?

What are closures in JavaScript? How do they work?

How does prototypal inheritance work in JavaScript?

Explain the event loop and its role in JavaScript.

What is the difference between "==" and "===" operators in JavaScript?

How do you handle asynchronous programming in JavaScript?

Explain the concept of promises and how they are used in JavaScript.

What are arrow functions in JavaScript? How do they differ from regular functions?

How does scoping work in JavaScript? Explain the difference between var, let, and const.

What is the purpose of the "this" keyword in JavaScript?

How do you handle errors and exceptions in JavaScript?

Explain the concept of callback functions and provide an example of their usage.

What is the difference between synchronous and asynchronous code execution in JavaScript?

How do you handle cross-origin resource sharing (CORS) in JavaScript?

What are the different ways to create objects in JavaScript?

Explain the concept of event bubbling and event capturing in JavaScript.

How do you handle form validation in JavaScript?

What is the purpose of the "use strict" directive in JavaScript?

How can you prevent the default behavior of an event in JavaScript?

Explain the concept of debouncing and throttling in JavaScript.

What are the different ways to manipulate the DOM in JavaScript?

How do you handle memory leaks in JavaScript?

Explain the concept of currying in JavaScript.

What are the different ways to iterate over an object in JavaScript?

How do you handle cross-site scripting attacks in JavaScript?

What do you think are the top benefits of immutability in JavaScript?

What are some new features introduced in recent versions of JavaScript that you have particularly been enjoying working with??

Ready To Hire JavaScript Developers With The Help Of Our Nearshore Software Development Services?

At Blue Coding, we understand that hiring JavaScript developers is a strategic business decision that should be handled with the utmost care. From high development rates to a shortage of specialized domestic talent, there are many things that could make the recruitment process a challenge for your organization. That’s why we offer staff augmentation services to help you quickly expand your team with talented JavaScript developers who possess the necessary skills and expertise to meet your project goals. Through nearshore outsourcing, we can grant you access to a diverse and affordable pool of Latin American developers that are ready to start working immediately. Not only can we help you hire JavaScript developers, but we’ll also handle the bulk of the hiring process, from the key interview questions to professional background checks, with the help of our expert technical recruitment team. Ready to get started with JavaScript development for a lower cost? Contact us today to learn more about our nearshore software development services! 

Enjoyed reading it? Spread the word

Subscribe to the
Blue Coding Weekly Rundown

Get helpful tips on remote jobs, our latest job openings, and more!