Top React Coding Questions 2021

Let’s say you’re looking to hire a software engineer who is familiar with the ReactJS library. You might be concerned because you haven’t seen any actual coding done on the front end in your interviews. And you know that this person has to be able to work with your team. You decide to try out a few coding challenges.

The first candidate sends back an exercise that includes all of the knowledge they gained through personal study and hard work. Their solution is correct, but they didn’t include enough comments for anyone on your team to understand it.

The next candidate only knows the basics. They use seven different lifecycle methods in their code… and they’ve done it all wrong.

It seems like finding a React expert is harder than it looks.

Ultimately, you want the candidate to send back an assessment that’s well documented and organized. You want a person who knows what they’re doing and who will be able to get things done efficiently.

Enter: React coding questions.

React interview coding challenges start simple and get gradually more complex. They’re designed to allow you and your team to gain a better understanding of who the candidate is and what they know. During a live coding test, you’ll be able to open up the hood and see how they think, all while seeing what happens when you start messing around with their code.

Let’s take a look at some questions you can put in front of React job applicants.

What is ReactJS?

ReactJS is a front-end JavaScript library developed by Facebook in 2011 to handle the view layer for web applications. It’s since become one of the most popular tools of its kind, boasting more than 79,000 stars on GitHub.

React is “isomorphic” — meaning that it can be used for both server-side rendering and client-side rendering. It’s useful in developing user interfaces because it lets developers create virtual views based on data provided by real views. Other benefits of ReactJS include:

• Easier to iterate design and create new features

• Flexibility when building user interfaces

• Less time debugging thanks to virtual views

• A more stable development platform between the front-end and the back-end

Can you get a job in the industry without knowing how to code in React?

Not knowing React is like not having written in English. You can get by for a little while, but eventually, you’re going to need to be able to write in order to communicate your ideas efficiently and effectively.

ReactJS has become an essential skill because it’s used on the front-end of websites. If you want to make a website or web application, understanding how ReactJS works is a necessary step.

Questions interviewers ask

Wondering how to interview someone who knows React? You’ll want to watch them work in an online code editor. This lets you see what kind of solution the person can come up with and how they go about writing their code. You’ll also want them to be able to explain each step in the process while providing details about why they chose a certain approach.

ReactJS coding challenges start out simple. A good interview candidate should be able to create an HTML file, then add JavaScript code that uses the React library.

You can ask them to use Babel (a JavaScript compiler) and Webpack (a module bundler) as well. The more familiar they are with these tools, the better they’ll be able to use them on your team.

From there, you can ask a candidate to:

• Use JSX (JavaScript XML) and build a functional React app.

• Create stateless and stateful components with JavaScript functions and class properties.

• Add an event listener using events from the React object.

• Add a React Router to a web page and pass parameters from one route to other.

• Create a custom component with properties, state, and lifecycle methods other than those inherited from the PureComponent base class.

• Use propTypes to check that all props are correct before rendering.

• Add static methods to a class component by adding a method called “statics.”

• Create React hooks with classes, functions, or objects using the useState hook.

• Fetch data from an endpoint using the fetch API and React’s componentDidMount lifecycle hook.

• Create an asynchronous React app using promises, callbacks, and the async/await pattern.

If you’re not sure whether a candidate will be able to handle React coding challenges on your team, ask them to build something that helps you visualize the problem they’ll be solving or learn more about their past work.

What are some benefits of a live coding interview?

Some developers can write code on a page without too much trouble, but what about when you ask them to write that same code live?

This is where a live coding test can be helpful. Working with a candidate in an online code editor highlights how well they know React and allows you to see their thought process.

Keep in mind that this requires synchronous time between the candidate and interview evaluator, which unfortunately creates unnecessary stress for the candidate.

Here are some of the most common online coding interview tools:

  • Leetcode: Leetcode contains a variety of coding challenges across multiple programming languages. While preparing for an interview, it’s a good idea for your candidate to complete at least a few of these challenges, and you can ask questions about the ones they get wrong.
  • Codeshare: Codeshare allows you to see how someone writes code by creating an online programming session. You’ll be able to upload your own sample project or pick one from the site’s list of public projects.
  • Coderpad: Coderpad has simple tutorials that explain how to use the online editor, then it gives you a coding challenge. You can see your candidate’s code and the console log in real-time, plus you can add technical specifications so they know what to expect.

As the React team continues to expand, so does the demand for skilled developers. That means more and more companies are looking for talent all over the world. If you’re able to see a candidate’s ability by giving them real engineering work to perform, it’s a good indicator of their future success.

What are some disadvantages of a live coding interview?

One major downside of a live coding interview is that it can be stressful for candidates. They’re not only trying to do their best but also worrying about how they’re performing in front of a panel of interviewers. Plus, how often do engineers have to come up with code on the spot in front of a boss?

Many developers don’t like to do interviews, and while some can work on a problem with someone looking over their shoulder, others really struggle in this type of situation. That doesn’t necessarily mean they’re a bad fit for the role.

One option is to provide a list of live coding interview tips to candidates.

Another option is to leverage an interview tool that’s asynchronous so they can work alone and show off their skills.

Woven’s asynchronous technical assessment platform is a good example of this because it allows your candidate to solve problems at their own pace, on their own time. It also helps you find hidden gem developers that may have otherwise been rejected.

How long do interviews last?

Software engineering interviews are notoriously long. Most last for at least an hour, and some companies have a marathon process where they bring in candidates for back-to-back interviews without stopping.

That eats up a lot of engineering time.

It’s a good idea to schedule a coding interview length that’s practical for your company and works with your candidate’s schedule. Then, once you have a better idea of their skills and knowledge, you can dive into more in-depth software developer technical interview questions.

Why are software engineering interviews so hard?

As it turns out, React is just one part of what you hire a great software engineer to do. Solving problems, managing complex systems, debugging code, and having architecture and design skills are just as important as having a strong knowledge of React.

The developer must understand your business and what you expect from them. That’s why you need to ensure your candidates can do more than just code under pressure.

Your company should have an effective hiring process that includes a variety of interview types to determine how well they’ll perform in the role. With Woven’s technical assessment, you can find out how they would approach a problem, what information they’d need to solve it, and how confident they are in their solution.

To learn more, start a free trial today.