Coditas Technologies Interview Questions and Answers for Experienced

Implementing document upload and preview in React involves file input handling and rendering previews based on file type.

• Use an <input type='file'> element to allow users to select documents.

• Utilize FileReader API to read the file and generate a preview.

• Handle different file types (e.g., images, PDFs) with conditional rendering.

• Implement state management (e.g., using useState) to store the selected file.

• Example: ...read more

Create an analog clock in React using state and CSS for styling.

• Use React's useState and useEffect hooks to manage time updates.

• Create a Clock component that renders the clock face and hands.

• Calculate the angles for the hour, minute, and second hands based on the current time.

• Use CSS transforms to rotate the clock hands appropriately.

• Set an interval to update the clock every second.

Webpack is a module bundler, while Vite is a build tool that focuses on speed and modern development experience.

• Webpack bundles JavaScript modules, while Vite serves files directly during development for faster refresh.

• Vite uses native ES modules in the browser, allowing for on-demand loading, whereas Webpack bundles everything upfront.

• Webpack requires configuration for various features, while Vite offers sensible defa...read more

React 19 introduces new features enhancing performance, developer experience, and concurrent rendering capabilities.

• Automatic Batching: React 19 allows automatic batching of updates, improving performance by reducing the number of renders.

• New Suspense Features: Enhanced support for Suspense, allowing for better handling of asynchronous data fetching.

• Concurrent Rendering Improvements: Further optimizations for concurren...read more

useState manages state and triggers re-renders; useRef holds mutable values without causing re-renders.

• useState is used for state management, while useRef is used for accessing DOM elements or storing mutable values.

• useState triggers a re-render when the state changes, whereas useRef does not trigger re-renders.

• Example of useState: const [count, setCount] = useState(0);

• Example of useRef: const inputRef = useRef(null);

• u...read more

Context is for simpler state management, while Redux is a more robust solution for complex state management in React applications.

• Context API is built into React, while Redux is a separate library.

• Context is suitable for light state management, whereas Redux is ideal for large applications with complex state.

• Context can lead to performance issues if not used carefully, while Redux provides optimized performance through...read more

List allows duplicate elements and maintains insertion order, while Set does not allow duplicates and does not maintain order.

• List can contain duplicate elements, while Set cannot.

• List maintains the order of elements based on insertion, while Set does not guarantee any specific order.

• Examples: ArrayList is a List implementation, HashSet is a Set implementation.