Frequently Asked Questions
What are the main features of React?
Whether it’s ReactJS’s ability to access/establish a virtual DOM or single-way data flow, ReactJS and its continual open source development are scaling in versatility and purpose in the front-end development sector.
Senior React Developer salaries are hard to pin down, and depending on which platform you look at will produce different results. To better understand the why behind senior ReactJS developer salaries, we must first understand the industry, company stage, size, and resources available to those businesses to hire.
Regardless, we can still get a general sense of the salary amount for senior React developers.
Senior React developer salaries
Again, the salaries across platforms aren’t uniform. A quick search on ZipRecruiter, Glassdoor, and Levels will produce similar but different results.
The average senior ReactJS developer salary in the United States across all industries is between $110k/yr and $150k/yr. Top performers earn upwards of $169k/yr to $176k/yr, while below-average earners make around $82k/yr to $100k/yr.
According to Glassdoor and ZipRecruiter, senior ReactJS developers can be as low as $87k and upwards of 178k in the United States. Keep in mind that these sites take a very broad look at developer salaries across many industries.
Glassdoor estimates that the average salary for a senior React developer with 7-9 years of experience is $116k in the United States. That average raises to $127k for senior ReactJS developers with 10-14 years of experience.
ZipRecuiter doesn’t make any distinction between years of experience and instead puts the average at $134k and shows the percentage distribution of salaries between $88k and $176k. Their data states that over 14% of senior React.js developers are making salaries in one of three different tiers, specifically the $104-112k, $128k-$135k, and $136k-$143k ranges.
Sites like Levels focus specifically on the tech industry and Silicon Valley-caliber positions where salaries become even more granular. This is due to the leveling systems that big tech companies use to distinguish seniority.
You’ll often see prefixes such as L4 or L5 to determine the “level” of a developer. Salary bands and percentile distributions increase with each level.
According to Levels, the median salary is $169k, with the 25th percentile making around $112k. The 75th% and 90th% make around $230k and $305k respectively. Keep in mind these are extremely competitive roles at the best tech companies.
Why are salaries so different (and high) across tech?
The broad salary variance is directly related to the location and cost of living where these positions are available. Resources also play a part as well-funded companies will pay more to attract the best talent. We saw plenty of this during the “talent wars” where companies such as Netflix paid top dollar to hire the best developers the United States had to offer. In fact, sites like Levels exist purely because of big-tech companies paying top dollar for top talent.
As a result of the “talent wars”, smaller companies weren’t able to hire senior talent as fast. Senior developers were especially challenging to find as they aren’t usually in the job market. Getting a solid senior developer took substantial recruiting efforts and a high offer.
Senior ReactJS developer salary vs other technologies
VueJS: $91k ($73k-$116k) High: $143k | Low: $59k (Glassdoor)
Angular: $104k ($85k-$131k) High: $159k | Low: $70k (Glassdoor)
React: $116k ($97k-$142k) High: $169k | Low: $82k (Glassdoor)
Is the cost of a senior ReactJS developer worth it?
If you are looking to build a new web or mobile application or get more done on a currently existing product with a small team, then the answer is yes. Senior developers unlock your roadmap by orders of magnitude compared to junior and mid-level developers.
Hiring senior ReactJS developers can be either seen as a profit center (investment) or a cost center (expense). To a finance executive, all of this is considered OpEx and it’s no secret that engineering departments are the most expensive to run.
We expect that the costs of building great software are made whole through solid product market fit, and great marketing/sales strategies to capture value. So it’s extremely important that you build a team with senior talent that moves the product roadmap forward in collaboration with other teams, and build software that feels as good as it looks.
You need to hire senior React developers that understand the big picture of building products and, apply their craft and experience effectively in a remote team environment, and value communication to make magic happen.
Unfortunately, high-caliber developers aren’t easy to find and even harder to identify. The costs of making a wrong hire are extremely high. If you’re looking for senior ReactJS developers that can help you get more done and make a real impact in your business, try working with one of our Trio senior React developers.
3 min read
Senior React.js interview questions and answers for 2023
The way you interview senior React developers is different than how you would for junior and mid-level roles. This is because the roles, responsibilities, and skill requirements are very different between each level.
For senior React developers, specifically, there’s a large emphasis placed on years of experience. Experience is the one signal that will determine whether a developer has seen enough in the wild to come up with meaningful solutions based on, well, their experiences!
Mind blown? Don’t worry, it gets better.
Of course, we expect senior React developers to know the fundamentals of their library of choice, and they should also be able to solve a variety of popular advanced cases that make user experiences feel delightful and truly high-quality.
But more importantly, they need to communicate well with their team and demonstrate real-world experience through the stories they tell. It’s very hard to fake the experience.
If you’re looking to properly interview and validate your senior React developers on a technical and non-technical level, we got you covered. Below are some technical and non-technical questions you can use in your next interview.
Technical Questions for senior react developers
Is there a way to cancel a request inside a useEffect?
The following code doesn't preserve the component state when isFavorite changes, how can you prevent/fix this?
When a component is rendered in a React app, its state is preserved as long as it remains in the UI tree. This can cause issues if the component is unmounted and then remounted at a different position in the tree, as its state will be lost.
To prevent this, you can render the component within the same parent div to ensure that its state is preserved even if it is moved around in the UI tree. This way, the component can be safely unmounted and remounted without losing its state.
What's the main difference between useMemo and useCallback and when would you want to use and avoid them?
The useMemo hook is used to memoize the value of a function, optimizing expensive calculations, while useCallback is used to memoize the function itself, optimizing the performance of child components.
Use useMemo when you want to memoize a value and avoid recomputation, and use useCallback when you want to memoize a function and prevent unnecessary re-renders of child components.
Use it: useMemo is used when you want to optimize the performance of expensive calculations or complex operations that are not related to rendering. It allows you to avoid unnecessary recalculations when the inputs haven’t changed.
Don't use it: useMemo should not be used for side effects or as a replacement for useEffect. If you need to perform an action that has side effects (such as modifying the DOM or fetching data), you should use useEffect instead.
Use it: useCallback is used when you want to optimize the performance of child components that rely on callbacks. By memoizing the callback function, you can ensure that child components only re-render when the dependencies of the callback change, rather than on every render.
Don't use it: useCallback should not be used excessively or prematurely. It’s best to use it when you notice actual performance issues related to unnecessary re-renders of child components.
React Problem/Scenario Questions
These questions are quasi-technical questions that focus on general problem-solving within the context of ReactJS.
How do you ensure that React components are shared effectively across your development team and well documented so that everyone has access to the latest version of each component?
Of course, there are no wrong answers here but a good alternative is to use Storybook. With Storybook you are able to build UI components and pages in isolation. Some cool benefits of Storybook:
- Tests: Visual tests, interaction tests, accessibility tests, coverage tests, and snapshot tests.
- Documentation: generate UI docs automatically
- Reusability: reuse components across pages and apps
- History: track components' history and versions
If you want to install it in your application, please follow these steps.
Non-technical questions for senior React developers
Could you tell us about a project where you had to integrate React.js with other technologies/platforms?
It's common to combine platforms and technologies with React.js. This question is used to assess a candidate's familiarity with integrating React.js into different contexts as well as their versatility when it comes to using different tools and technologies.
A good answer to this question is a story where they demonstrate their overcoming the challenges associated with integrating React. They’ll present details that would be hard to fabricate otherwise.
There is no wrong answer to this question, only vague answers that indicate that the developer chose not to be honest about the fact that they did not integrate React. The signal to consider is that in cases where they might be under pressure, they might provide misinformation which can be problematic down the road.
How do you ensure that your code is maintainable and easy for others to understand and work with?
Maintainable code is code that is easy to read, understand, and modify.
Keep in mind that other developers will work with your code when creating a React.js application, therefore you should make sure it is as simple as possible for them to do so.
It's important to describe the steps you take to ensure that your code is maintainable. Be sure to mention descriptive variable naming, breaking code down into smaller pieces, modularization, separation of concerns, etc.
Great teams think about these types of things in advance. They create code standards and guidelines that ensure consistency across the codebase no matter who is writing.
Senior ReactJS developers who come from teams like these will know and understand the value of standardization and will most likely seek to continue working on teams that share their values.
3 min read
The choice of a front-end framework is a pivotal decision that can significantly impact the success of your web development project. In the ever-evolving landscape of web development, NextJS and ReactJS have emerged as two prominent options garnering widespread adoption.
This article delves deep into the intricacies of NextJS and ReactJS, shedding light on their unique features, benefits, and key considerations.
By gaining a comprehensive understanding of these frameworks, you will be equipped to make an informed decision that aligns with your project's requirements and sets you up for success.
What is React
This approach allows developers to build reusable and modular components, making code organization and maintenance a breeze. Additionally, ReactJS utilizes a virtual DOM (Document Object Model) to efficiently update and render UI elements, resulting in better performance and a smoother user experience.
React’s key features include:
- Component reusability: React promotes the creation of modular and reusable UI components, making it easier to build complex interfaces.
- Virtual DOM: React's virtual DOM efficiently updates only the necessary parts of the user interface, improving performance.
- Unidirectional data flow: React follows a one-way data flow, making it easier to track changes and maintain application state.
- Rich ecosystem: React has a vast ecosystem of libraries, tools, and community support, making it suitable for a wide range of use cases.
The ReactJS ecosystem is vibrant and constantly evolving. It offers a wide range of third-party libraries, tools, and community support. Developers can find solutions for various requirements, from state management (using hooks like useState and useContext) to global state management (with Redux).
The availability of numerous resources, forums, and tutorials ensures that learning ReactJS is both accessible and rewarding.
What is NextJS
Next.js, built on top of React, is a framework specifically designed for server-side rendering (SSR) and static site generation (SSG) in React applications.
Some key features and benefits of Next.js are:
- Server-side rendering (SSR): Next.js allows rendering React components on the server before sending them to the client, resulting in faster initial page loads and improved SEO.
- Static site generation (SSG): Next.js supports pre-rendering of entire pages at build time, enabling the generation of static HTML files for improved performance and better caching.
- File-based routing: Next.js provides a simple and intuitive file-based routing system, eliminating the need for complex routing configurations.
- API routes: Next.js allows the creation of serverless functions called API routes, enabling the development of backend functionality within the framework itself.
These additions simplify the development process and reduce the need for additional libraries or configurations.
NextJS shares many key features with React, including component-based development and the virtual DOM, and combines the power of React with server-side rendering capabilities, allowing developers to pre-render pages on the server and deliver HTML to the client. This approach improves initial page load times, enhances SEO (Search Engine Optimization), and provides a better user experience.
Getting Started with React
To start using React, you need to set up a development environment. Here are the basic steps to get started:
- Installation and setup: Install Node.js and npm (Node Package Manager) to manage dependencies. Then, create a new React project using tools like Create React App or manually configure the project structure.
Getting Started with Next.js
Next.JS, being a framework built on ReactJS, requires a similar development environment setup. You will need Node.js and a package manager. Fortunately, NextJS provides a streamlined setup process with its built-in create-next-app command, allowing you to quickly initialize a Next.JS project with minimal configuration
To begin working with Next.js, follow these steps:
- Installation and setup: Install Next.js using npm or yarn. Create a new Next.js project using the provided command-line interface (CLI) tool or manually set up the project structure.
- Creating a basic Next.js project: Create a pages directory where each file represents a unique route. Define the structure and content of the page using JSX syntax. Next.js automatically handles the routing for these pages.
- Understanding server-side rendering (SSR): With Next.js, components can be rendered on the server and sent to the client as HTML, providing a faster initial page load. Understand how Next.js handles SSR and the benefits it offers.
Both React.JS and Next.JS rely on various tools and dependencies to streamline the development process. Some commonly used tools include code editors like Visual Studio Code, version control systems like Git, and development servers like webpack-dev-server.
Additionally, libraries like React Router, CSS-in-JS libraries for styling, and testing frameworks can be utilized to enhance the development workflow.
React's popularity has led to the growth of a vibrant ecosystem consisting of libraries, tools, and community support. Here are some essential components of the React ecosystem:
- React Router: React Router is a popular library that provides client-side routing capabilities, allowing you to create navigation within a React application.
- State management with Redux or MobX: React itself offers basic state management, but for complex applications, libraries like Redux or MobX are commonly used to manage application state more efficiently.
- UI component libraries: Several UI component libraries, such as Material-UI and Ant Design, offer pre-built UI components and styling options to streamline the development process.
These components enhance the development experience and provide ready-to-use solutions for common challenges in building React applications.
Next.js has its own ecosystem, offering additional features and tools to augment the development process. Some notable aspects of the Next.js ecosystem include:
- Server-side rendering (SSR) benefits: Next.js brings server-side rendering capabilities to React, allowing for faster page loads and improved search engine optimization (SEO).
- File-based routing: Next.js simplifies routing by mapping files and directories to URLs, reducing the need for complex routing configurations.
- API routes for serverless functions: Next.js provides a built-in API routing system, allowing you to create serverless functions that can serve as backend endpoints.
These features make Next.js an attractive choice for projects that require server-side rendering and seamless API development.
Building reusable components is a fundamental aspect of both React.JS and NextJS. React.JS promotes a component-based architecture, where you break down your user interface into modular components that encapsulate their own logic and can be reused across your application. This modular approach simplifies maintenance, promotes code reusability, and improves collaboration between team members.
Similarly, Next.JS encourages the use of components to create reusable UI elements. However, Next.JS takes it a step further by providing built-in features like Layouts and Partials. Layouts allow you to create consistent structures for your pages, while Partials enable you to reuse smaller components within your layout.
When creating components in React.JS and Next.JS, it's important to follow best practices. This includes writing clean and concise
When it comes to performance, both React and Next.js have their strengths and considerations. Here's a comparison of their performance aspects:
- Performance considerations in React: React's virtual DOM diffing algorithm optimizes rendering, minimizing costly updates to the actual DOM. However, React primarily relies on client-side rendering (CSR), which can result in slower initial page loads and potential SEO challenges.
- Benefits of server-side rendering (SSR) in Next.js: Next.js addresses React's limitations by enabling server-side rendering, resulting in faster initial page loads and better SEO. By rendering components on the server, Next.js provides a fully rendered HTML page, improving performance and user experience. Understanding the trade-offs and implications of performance in React and Next.js can guide your decision-making process based on your project's specific requirements.
SEO and Next.js
Search engine optimization (SEO) is a critical aspect of modern web applications. Let's explore how Next.js addresses SEO challenges compared to React:
- Importance of SEO for web applications: SEO helps improve the visibility of a website on search engine result pages, driving organic traffic and increasing user engagement.
- SEO benefits of server-side rendering (SSR) in Next.js: Next.js' server-side rendering capabilities generate fully rendered HTML pages on the server, ensuring faster initial page loads and better search engine indexing. By leveraging Next.js' SSR capabilities, you can enhance your application's SEO performance and achieve better visibility in search engine rankings.
Deployment and Hosting
Deploying and hosting React and Next.js applications involve different considerations. Here are some deployment options and hosting platforms for both frameworks:
- Deployment options for React applications: React applications can be deployed to various hosting platforms, including cloud providers like AWS, Google Cloud, or Azure, as well as static site hosting services like Netlify or Vercel.
- Deployment options for Next.js applications: Next.js applications can also be deployed to cloud providers or static site hosting platforms. Additionally, Next.js offers features like serverless deployment to serverless computing platforms like AWS Lambda or Vercel's serverless functions.
Choose a deployment option and hosting platform that aligns with your project's scalability, performance, and cost requirements.
When to Choose React
While Next.js builds upon React, there are scenarios where using React alone might be more appropriate:
- Scenarios where React is a better choice: If your project has minimal server-side rendering (SSR) requirements and focuses on building client-side rendered applications or leveraging React Native for mobile app development, using React alone can be a suitable option.
- Projects with a different backend technology: If your project involves integrating with a custom server or a backend technology other than Node.js, using React without Next.js may offer more flexibility. Understanding these scenarios will help you determine if React is the ideal choice for your specific project requirements.
When to Choose Next.js
Next.js excels in scenarios that demand server-side rendering, improved SEO, and a simplified development experience for server-rendered applications. Here are some instances where Next.js shines:
- Scenarios where Next.js is a better choice: If your project requires server-side rendering (SSR) to enhance performance and SEO, or if you want a streamlined development experience with file-based routing and built-in API routes, Next.js is a powerful framework to consider.
- Projects with a need for enhanced SEO: Next.js' server-side rendering capabilities provide fully rendered HTML pages, ensuring better search engine indexing and improved SEO performance.
Next.js empowers developers to build performant, SEO-friendly applications with ease, making it a compelling choice for certain project requirements.
Should Your Hire A React or Next.js Developer?
Hiring React and Next.js developers can be a crucial step in ensuring the success of your projects. Consider the following technical aspects when hiring developers proficient in React and Next.js:
- Proficiency in React ecosystem: Look for candidates who have a solid understanding of the React ecosystem, including popular libraries and tools such as Redux, React Router, and styled-components. They should be familiar with best practices for state management, routing, and styling in React applications.
- Understanding of component-based architecture: React follows a component-based architecture, so candidates should have experience in building reusable and modular components. They should understand concepts like props, state, lifecycle methods, and hooks. Assess their ability to structure and organize components effectively.
- Experience with Next.js features: If you specifically require Next.js expertise, evaluate candidates' knowledge of Next.js specific features such as server-side rendering (SSR), static site generation (SSG), and API routes. Assess their ability to leverage Next.js to optimize performance, handle data fetching, and build server-rendered applications.
- Testing skills: React and Next.js applications can benefit from comprehensive testing. Look for candidates who have experience with testing frameworks and libraries like Jest, Enzyme, or React Testing Library. Assess their ability to write unit tests, integration tests, and end-to-end tests for React and Next.js components.
- Performance optimization: React and Next.js developers should be knowledgeable about performance optimization techniques. Evaluate candidates' understanding of code splitting, lazy loading, memoization, and other performance optimization strategies in React applications. Assess their ability to identify and resolve performance bottlenecks.
- Version control and collaboration tools: Proficiency in version control systems like Git and collaboration platforms like GitHub or GitLab is crucial for team collaboration. Ensure candidates have experience using Git for code versioning, branching, merging, and collaborating with other developers using pull requests.
- Familiarity with front-end build tools: Candidates should be familiar with front-end build tools like Webpack, Babel, and npm/yarn. Assess their ability to configure and customize build processes, handle dependencies, and optimize the bundling and minification of assets.
- Knowledge of responsive and mobile-first design: React and Next.js developers should understand responsive design principles and be able to build applications that work well across different devices and screen sizes. Assess their knowledge of CSS media queries, flexbox, and CSS Grid for responsive layouts.
- Problem-solving and debugging skills: Assess candidates' problem-solving and debugging abilities by asking them about challenging scenarios they encountered while working with React and Next.js. Evaluate their logical thinking, troubleshooting strategies, and familiarity with debugging tools like browser developer tools.
By considering these technical aspects during the hiring process, you can ensure that the React and Next.js developers you hire have the necessary skills and expertise to contribute effectively to your projects.
Choosing the right framework between Next.js and React depends on various factors. React offers a powerful library for building user interfaces, while Next.js extends React with features like server-side rendering (SSR) and simplified routing.
By understanding the features, benefits, and use cases of both frameworks, you can make an informed decision that aligns with your project requirements. Consider the performance implications, SEO considerations, and deployment options to determine whether React or Next.js is the best fit for your specific use cases.
If you’re considering hiring a senior React developer that knows Next.js and hoping to save a ton of time screening and interviewing, consider working with a tech partner like Trio to hire faster and smarter.
8 min read