Which of the following is NOT a valid reason to choose class components over functional components?
- Better performance.
- Legacy codebase with class components.
- Need to use lifecycle methods extensively.
- A preference for class-based syntax.
Better performance is NOT a valid reason to choose class components over functional components. In fact, functional components are often more performant due to optimizations made by React in recent versions. The other options, such as legacy codebase, extensive use of lifecycle methods, or personal preference for class-based syntax, can be valid reasons to choose class components in some cases.
To customize the Next.js configuration, you would create or modify the ________ file.
- next.config.json
- package.json
- .env.local
- .babelrc
To customize the Next.js configuration, you would create or modify the next.config.json file. This JSON file allows you to configure various aspects of your Next.js application, including customizing webpack, setting environment variables, and more. The other options are not used for customizing Next.js configuration directly.
For better performance in a React application, offloading ________ tasks to Web Workers can be beneficial.
- Computational
- Debugging
- Rendering
- Server-side
Offloading computational tasks to Web Workers in a React application can be beneficial for better performance. This allows these tasks to run in the background without blocking the main UI thread, ensuring a smoother user experience. This approach is commonly used for tasks like complex calculations or data processing.
In which scenario would using a Portal be more beneficial than a traditional React component rendering approach?
- When you need to enforce strict hierarchical rendering within a component tree.
- When you need to render a UI element in a different DOM position than its parent while maintaining event relationships.
- When you want to handle asynchronous data fetching in a React application.
- When you want to simplify your component tree by reducing the depth of nested components.
Portals are beneficial when you need to render a UI element outside its parent's DOM hierarchy while preserving parent-child event relationships. This is especially useful for modals, tooltips, and popovers. Portals do not primarily aim to simplify the component tree or handle data fetching asynchronously. They are not related to enforcing hierarchical rendering.
In functional components, to manage local state you can use the ________ hook.
- useContext
- useEffect
- useRef
- useState
In functional components in React, you can manage local state using the useState hook. This hook allows you to add state variables to your functional components, providing a way to manage and update component-specific data without using class components and this.state.
Which of the following is a popular library for styling components in React?
- Axios
- React Query
- Redux
- Styled-components
Styled-components is a popular library for styling components in React. It enables developers to write CSS-in-JS, allowing them to create styled components with ease. React Query, Axios, and Redux are not primarily used for styling; React Query and Axios are used for data fetching, and Redux is used for state management.
Imagine you're building a slide show in React where slides transition with a fade effect. Which component from React Transition Group would be the most appropriate choice?
In React Transition Group, the appropriate choice for creating a fade effect in a slide show is
The hook that provides a way to fetch and dispatch to a React context is ________.
- useContext
- useEffect
- useReducer
- useState
The hook that provides a way to fetch and dispatch to a React context is "useReducer." While "useContext" allows components to access the context, "useReducer" is typically used for state management within the context and provides a way to dispatch actions for state updates.
If you want to persist state across re-renders without causing any side effect, you'd use the ________ hook.
- useContext
- useEffect
- useMemo
- useRef
When you want to persist state across re-renders without causing any side effects, the useRef hook is typically used. Unlike other hooks like useEffect or useMemo, useRef does not trigger re-renders or side effects, making it ideal for maintaining mutable values that persist between renders.
Which of the following considerations is most crucial when scaling a React application with thousands of active Websocket connections?
- Minimize the usage of server-sent events (SSE) for real-time updates.
- Optimize server-side code and infrastructure to handle concurrent connections.
- Use traditional HTTP polling instead of Websockets for better scalability.
- Decrease the number of components that subscribe to Websocket updates.
When scaling a React application with thousands of active Websocket connections, the most crucial consideration is optimizing server-side code and infrastructure to handle concurrent connections (Option 2). This ensures that the server can manage the load effectively. The other options do not address the scalability challenges associated with a large number of Websocket connections. Server-sent events (SSE) and HTTP polling are not necessarily better alternatives for real-time updates. Reducing the number of subscribing components may impact the application's functionality.