Which of the following is the correct way to render multiple children without adding extra nodes to the DOM in React?
- Use a JavaScript array to render each child separately.
- Use a React.Fragment wrapper around the children components.
- Use a div element to wrap the children components.
- Use conditional rendering to display children one at a time.
The correct way to render multiple children without adding extra nodes to the DOM in React is by using a React.Fragment wrapper around the children components. This approach avoids introducing unnecessary nodes to the DOM while allowing you to group and render multiple components cleanly and efficiently.
One potential downside of Render Props is increased ________, especially if nested deeply.
- Complexity
- Performance
- Reusability
- Scalability
One potential downside of using Render Props is increased complexity, especially if they are nested deeply within components. While Render Props provide a powerful pattern for sharing behavior, they can lead to more complex code structures, which might be harder to maintain and understand, particularly when deeply nested.
What is the main drawback of overusing Render Props in a React application?
- Prop drilling
- Reduced component reusability
- Increased component performance
- Improved code maintainability
Overusing Render Props can lead to reduced component reusability. While Render Props are a valuable pattern for sharing code, excessive use can make components less versatile and harder to maintain. Prop drilling (Option 1) is a related issue but not the main drawback of Render Props. Render Props can also introduce some performance overhead, but this isn't their primary drawback. Improved code maintainability (Option 4) is a potential benefit, not a drawback.
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.
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.
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.
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.
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.
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
In JSX, the HTML attribute class is replaced with ________.
- class
- className
- classTag
- cssClass
In JSX, the HTML attribute class is replaced with className. This is because class is a reserved keyword in JavaScript, and JSX is a JavaScript extension. To apply CSS classes to JSX elements, you should use className instead of class.
You're building an application where certain operations should only be performed when specific observable properties change. How would you set up a reaction that specifically listens to these properties in MobX?
- When
- autorun()
- computed()
- reaction()
To set up a reaction that specifically listens to certain observable properties in MobX, you would use the reaction() function. The reaction() function allows you to define custom reactions that depend on specific observables. When the specified observables change, the reaction is triggered, allowing you to perform the desired operations. This approach is suitable when you need fine-grained control over reactions.
When using the map function to render a list in JSX, it's important to provide a unique ________ to each item.
- Class
- Element
- Index
- Key
When rendering lists in JSX using the map function, it's crucial to provide a unique "key" to each item. This "key" is used by React to efficiently update and re-render elements in the list when needed. Using a unique key helps React identify which elements have changed, been added, or been removed, optimizing performance and preventing rendering issues.