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20 Must-Know Questions for Senior Frontend Interviews

Andrej Vajagic

Andrej Vajagic

18.12.2023, 16:26

Read time: undefined mins

20 Must-Know Questions for Senior Frontend Interviews

Certainly! Here's a list of 20 general technology interview questions tailored for a Senior Frontend Role. These questions cover a range of topics relevant to frontend development, from basic concepts to more advanced areas:

1. Can you explain the Document Object Model (DOM)?

Answer: The DOM is a programming interface for web documents. It represents the page structure as a tree of objects, allowing scripts to read and manipulate the page's content, structure, and styles.

2. What is the difference between == and === in JavaScript?

Answer: == checks for equality with type coercion, while === checks for both value and type equality without coercion.

3. How do you ensure your JavaScript code runs efficiently?

Answer: This involves optimizing algorithms, minimizing DOM manipulations, using efficient event handling, leveraging web workers for heavy tasks, and avoiding memory leaks.

4. Explain the concept of a Single Page Application (SPA) and how it works.

Answer: A SPA is a web application that loads a single HTML page and dynamically updates content as needed without refreshing the entire page. This is typically achieved using AJAX and HTML5 pushState().

5. What is the role of HTTP/HTTPS in web development?

Answer: HTTP and HTTPS are protocols for transferring data over the web. HTTPS includes encryption for security and is essential for protecting sensitive data.

6. How do you ensure website accessibility and compliance with WCAG?

Answer: This involves using semantic HTML, ensuring keyboard navigation, providing alt text for images, ensuring proper contrast ratios, and using ARIA roles where necessary.

7. Can you describe Progressive Web Apps (PWAs) and their benefits?

Answer: PWAs are web applications that offer a native app-like user experience. They are reliable (load instantly), fast, and engaging, and work offline or on low-quality networks.

8. What are the benefits and drawbacks of using CSS frameworks like Bootstrap or Tailwind CSS?

Answer: Frameworks speed up development and ensure consistency. However, they may add bloat, offer less flexibility, and lead to a generic look if not customized.

9. Explain Cross-Origin Resource Sharing (CORS) and its importance.

Answer: CORS is a mechanism that allows restricted resources on a web page to be requested from a different domain outside the domain from which the resource originated, enhancing security.

10. What strategies would you use to optimize the performance of a web application?

Answer: Performance can be optimized by minimizing HTTP requests, enabling compression, optimizing media files, using caching, and leveraging Content Delivery Networks (CDNs).

11. How do you manage state in a large-scale JavaScript application?

Answer: State management can be handled using libraries and frameworks like Redux, Context API in React, or VueX in Vue.js, ensuring a predictable state flow.

12. What are WebSockets and how would you use them in a web application?

Answer: WebSockets provide a full-duplex communication channel over a single, long-lived connection, allowing for real-time data transfer between a client and a server.

13. Can you explain the concept of responsive design and mobile-first design?

Answer: Responsive design means creating web pages that look good on all devices. Mobile-first design involves designing for mobile first, then scaling up to desktop or other devices.

14. What are Service Workers and how do they contribute to web applications?

Answer: Service Workers act as a proxy between the web application and the network. They enable features like offline support, background syncing, and push notifications.

15. How do you approach testing in frontend development?

Answer: Testing can include unit tests, integration tests, and end-to-end tests. Tools like Jest, Mocha, and Cypress are commonly used for testing in frontend development.

16. What is the importance of Continuous Integration/Continuous Deployment (CI/CD) in frontend development?

Answer: CI/CD automates the building, testing, and deployment of applications, ensuring more reliable and frequent releases.

17. How do you handle security concerns in frontend development?

Answer: This includes validating user input, implementing Content Security Policy (CSP), using HTTPS, and being cautious with third-party libraries.

18. Explain the concept of micro-frontends.

Answer: Micro-frontends involve breaking up a frontend application into smaller, more manageable pieces, each responsible for a distinct feature of the application.

19. What are the key considerations when choosing a frontend framework or library?

Answer: Considerations include community support, performance, learning curve, scalability, and compatibility with other tools and libraries.

20. What trends or emerging technologies are currently impacting frontend development?**

Answer: Trends include the rise of frameworks like React, Vue, and Angular, the growing importance of performance and accessibility, the use of TypeScript, and the interest in server-side rendering and static site generation.


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