What is the primary advantage of using CSS-in-JS libraries like Styled-components in React?
- Better support for global styles
- Enhanced performance
- Improved code organization
- Reduced reliance on CSS preprocessors
The primary advantage of using CSS-in-JS libraries like Styled-components in React is improved code organization. Styled-components allow you to define component-specific styles directly within your JavaScript code, making it easier to manage styles in a component-centric way. While performance benefits can be realized, the main advantage is the organization of styles.
Which method in Immutable.js returns a new List with values appended to the end of the current List?
- .append()
- .concat()
- .insert()
- .push()
In Immutable.js, the .push() method is used to return a new List with values appended to the end of the current List. The other methods have different purposes; for example, .concat() is used to concatenate two Lists, and .insert() is used to insert values at specific indices. .append() is not a method in Immutable.js.
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.
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.
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.
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.
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.