How to use connect from React Redux?
- Use it as a HOC to connect a component to the Redux store
- Use it as a middleware for handling async actions
- Use it to create a new Redux store
- Use it to reset the Redux state
connect is a Higher Order Component (HOprovided by React Redux that allows you to connect a component to the Redux store. It provides the component with access to the store and allows the component to subscribe to changes in the store's state.
What is the difference between Real DOM and Virtual DOM?
- Real DOM is faster than Virtual DOM
- Virtual DOM is faster than Real DOM
- Real DOM is a physical representation of the web page, while Virtual DOM is a virtual representation
- Virtual DOM is a physical representation of the web page, while Real DOM is a virtual representation
The Real DOM is a physical representation of the web page, consisting of all the HTML elements, their attributes, and their relationships with each other. The Virtual DOM, on the other hand, is a lightweight JavaScript representation of the Real DOM. The Virtual DOM allows React to update the UI efficiently by minimizing the number of updates needed to the Real DOM.
What are inline conditional expressions?
- Expressions that are evaluated during compilation
- Expressions that are evaluated during runtime
- Expressions that are used to conditionally render components
- Expressions that are used to set component state
Inline conditional expressions in React are expressions that are used to conditionally render components based on a certain condition. They are typically used in JSX, and are written using the ternary operator. Inline conditional expressions are a simple and effective way to conditionally render components without the need for additional logic.
Why is a component constructor called only once?
- The constructor is called for each new instance of the component
- The constructor is not needed in functional components
- The constructor is not used in React components
- The constructor is only called when the component is first created
In React, the constructor is called only once when the component is first created. This is because the constructor is used to initialize the component state and bind event handlers, and these operations only need to be performed once. After the component has been created, subsequent updates will use the "componentDidUpdate()" method to update the state and re-render the component.
What is the stable release for hooks support?
- React 15
- React 16
- React 17
React Hooks were first introduced in React 16.8, and have been a stable feature of React since React 16.8.0. React 17 is the most recent stable release of React as of September 2021.
What is the benefit of styles modules?
- Styles modules allow for dynamic styling with props
- Styles modules allow you to use CSS with React components
- Styles modules are required for server-side rendering
- Styles modules prevent CSS class naming collisions
Styles modules in React allow you to avoid CSS class naming collisions by generating unique class names at runtime. This helps prevent conflicts with other styles in the project, and allows you to use descriptive class names without worrying about naming conventions.
What is the lifecycle methods order in mounting?
- componentDidMount, componentWillMount, componentWillReceiveProps
- componentDidMount, componentWillReceiveProps, componentWillMount
- componentWillMount, componentDidMount, componentWillReceiveProps
- componentWillMount, componentWillReceiveProps, componentDidMount
The lifecycle methods for mounting a component in React are as follows: componentWillMount, render, componentDidMount. The "componentWillMount" method is called before the component is mounted to the DOM, "render" is called to render the component, and "componentDidMount" is called after the component is mounted to the DOM.
How do you memoize a component?
- Use the "React.memo" higher-order component
- Use the "React.useMemo" hook
- Use the "componentDidUpdate" lifecycle method
- Use the "shouldComponentUpdate" lifecycle method
To memoize a component in React, you can use the "React.memo" higher-order component. This will prevent the component from re-rendering if the props have not changed. You can also use the "shouldComponentUpdate" lifecycle method or the "React.useMemo" hook to achieve similar results.
How do you make sure that user remains authenticated on page refresh while using Context API State Management?
- Use cookies to store the authentication token
- Store the authentication token in local storage
- Use session storage to store the authentication token
- Use a server-side session to store the authentication token
When using the Context API for state management in a React application, it is important to ensure that the user remains authenticated even if the page is refreshed. One way to do this is to store the authentication token in local storage, which persists even after the page is refreshed. This allows the application to retrieve the authentication token from local storage and use it to authenticate the user without requiring them to log in again.
How to avoid using relative path imports in create-react-app?
- Use absolute path imports with a "jsconfig.json" file
- Use environment variables with a ".env" file
- Use npm modules with the "dependencies" field in package.json
- Use webpack aliases with a "webpack.config.js" file
In Create React App, you can avoid using relative path imports by using absolute path imports with a "jsconfig.json" file. This will allow you to import modules from any directory in your project using a relative path, such as "src/components/MyComponent".