Why we need to pass a function to setState()?
- To avoid infinite loops
- To ensure proper synchronization of state updates
- To handle errors gracefully
- To improve performance
In React, we need to pass a function to the "setState" method in order to avoid infinite loops. If we pass an object directly, it can cause the component to re-render and update the state endlessly. By passing a function, we can ensure that the state is updated correctly and avoid these issues.
What are hooks?
- Functions that let you "hook into" React state and lifecycle features from functional components
- Functions that let you modify the DOM directly from React components
- Functions that let you render custom elements in React
- Functions that let you create reusable UI components in React
Hooks are functions that allow developers to "hook into" React state and lifecycle features from functional components. This means that functional components can now have state and lifecycle methods, making them more powerful and flexible. Hooks were introduced in React 16.8 and have since become a popular way of managing state and adding behavior to functional components.
How do you pass arguments to an event handler?
- By using the event object
- By using arrow functions
- By using the bind() method
- By using the apply() method
In React, arguments can be passed to an event handler by using arrow functions. Arrow functions allow parameters to be passed to the function when it is called, rather than when it is defined. This allows event handlers to receive arguments without causing unnecessary re-renders.
What is the difference between createElement and cloneElement?
- There is no difference
- createElement is a class method, while cloneElement is an instance method
- createElement is used to clone existing elements, while cloneElement is used to create new elements
- createElement is used to create new DOM elements, while cloneElement is used to clone existing elements
createElement is a method used to create new React elements, while cloneElement is a method used to clone existing React elements and pass new props to the cloned element.
What are stateless components?
- Components that are only used for layout
- Components that don't have any children
- Components that don't have any props
- Components that don't use any state
Stateless components, also known as functional components, are components that don't use any state. Stateless components are simpler and easier to test than stateful components, but they can't be used for more complex UI components that need to maintain state.
What is ReactDOMServer?
- A way to create dynamic forms in React components
- A way to handle routing in React components
- A way to manage state in React components
- A way to render React components on the server
ReactDOMServer is a module that allows you to render React components on the server. ReactDOMServer provides several methods for rendering components, including the renderToString method and the renderToStaticMarkup method.
What is React lazy function?
- A function that creates a lazy version of a component
- A function that returns a higher-order component
- A function that creates a new instance of a component
- A function that creates a new element in the DOM
React lazy is a function that creates a lazy version of a component. This lazy version is loaded only when it is actually needed, such as when a user navigates to a page that requires the component. This can help improve performance by reducing the initial load time of the application.
What is your favorite React stack?
- MERN (MongoDB, Express, React, Node)
- MEAN (MongoDB, Express, Angular, Node)
- MEVN (MongoDB, Express, Vue, Node)
- Other
This is a subjective question and the correct answer will vary depending on the individual's experience and preferences. There is no one "correct" answer.
Why should not call setState in componentWillUnmount?
- Because it will cause a memory leak
- Because it will trigger a re-render after the component is unmounted
- Because the component's state is no longer available after unmounting
- Because it is unnecessary and can cause performance issues
The componentWillUnmount() method is called immediately before a component is unmounted and destroyed. It is not safe to call setState() within this method, as the component's state is no longer available after unmounting. Attempting to update the state after unmounting can cause errors or unexpected behavior in the application.
What is the purpose of displayName class property?
- To set the name of the component's file
- To set the name of the component for debugging purposes
- To specify the component's DOM display style
- To set the component's initial state
The displayName class property in a React component is used to set the name of the component for debugging purposes. This name is used in error messages and in the React Developer Tools to help identify the component in the component hierarchy. If the displayName property is not set explicitly, React will attempt to infer the name of the component from the name of the component class or function.