React test

The React test assesses the candidate’s ability to develop interactive and dynamic user interfaces using React, a popular JavaScript library for building UI components. The test begins by evaluating the candidate’s understanding of core React concepts, such as JSX, which allows developers to write HTML-like syntax directly within JavaScript code. It covers how React components are created, structured, and how they manage state and props to render dynamic content based on user interactions or data changes.

A key focus is on functional and class components, emphasizing the differences, use cases, and best practices for each. The test also evaluates the candidate’s proficiency in using React Hooks, particularly `useState`, `useEffect`, and custom hooks, to manage side effects, component lifecycle, and local state in functional components.

Routing with React Router is another crucial area, where candidates are asked to demonstrate how to implement client-side routing for single-page applications (SPAs). Candidates should be able to manage routes, nested routes, and dynamic route parameters, enabling smooth user experiences without page reloads.

The test further delves into performance optimization, with candidates expected to understand React’s virtual DOM and how it updates the real DOM efficiently to prevent unnecessary re-renders. Techniques such as code splitting, lazy loading, and memoization are assessed to ensure the performance of large React applications.

Understanding React’s component lifecycle, particularly in relation to state updates and re-renders, is another area covered in the test. Candidates must demonstrate competence in handling forms, validation, and managing form state within React.

Integration with APIs and asynchronous data fetching is a significant part of the test. Candidates are expected to show how React interacts with external libraries like Axios or the Fetch API to retrieve data and display it in components.

Error handling is another focus, with candidates required to understand how to use error boundaries to recover gracefully from runtime errors.

Lastly, candidates should have experience with testing React components using tools like Jest and React Testing Library to ensure their applications function as expected.