React 面试题与答案

问题 31. What are higher-order components (HOCs) used for?

HOCs are used for a variety of tasks such as:

• Manipulation of props
• State manipulation and abstraction
• Render highjacking
• Code reusing
• Bootstrap abstraction

问题 32. Differentiate between a controlled component and an uncontrolled component in React.

A controlled component, as the name suggests, is a component over which React has complete control. It is the singular point of data for the forms.

An uncontrolled component is one where the form data gets handled by DOM and not the React component. This is usually done using refs in React.

问题 33. How can you tell React to build in the production mode?

React can be coded to directly build into production by setting the process.env.NODE_ENV variable to production.

Note: When React is in production, warnings and other development features are not shown.

问题 34. What is the difference between cloneElement and createElement in React?

In React, cloneElement is primarily used to clone an element and pass it to new props directly. Whereas, createElement is the entity that JSX gets compiled into. This is also used to create elements in React.

Next up on this top React interview questions and answers blog, take a look at the use of the second argument.

问题 35. What is the StrictMode component used in React?

The StrictMode component when used would benefit users immensely while creating new codebases to understand the components being used.

However, it can fit well in debugging as well because it will help solve the problem faster when it is wrapped with other components, which could be causing the problem.

Next up on these interview questions on React JS, you have to understand how to speed up rendering.