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.

What are the lifecycle methods going to be deprecated in React v16?

  • componentWillMount and componentWillReceiveProps
  • componentWillMount and componentWillUpdate
  • componentWillReceiveProps and componentWillUpdate
  • componentWillUpdate and componentDidUpdate
The "componentWillReceiveProps" and "componentWillUpdate" lifecycle methods are going to be deprecated in React v16. These methods will be replaced with new lifecycle methods that are more efficient and easier to reason about. The new methods are "getDerivedStateFromProps" and "getSnapshotBeforeUpdate".

How to get history on React Router v4?

  • Use the "history" object provided by the "history" module
  • Use the "history" object provided by the "react-router-dom" module
  • Use the "this.history" object provided by the router
  • Use the "this.props.history" object passed to the component
In React Router v4, you can get the history object by using the "this.props.history" object passed to the component. This object contains the current history of the router, including the current location, previous locations, and navigation history. You can use this object to programmatically navigate, access the current URL, or manage the browser history.

How to dispatch an action on load?

  • Use a lifecycle method in a component
  • Use a middleware
  • Dispatch the action in the reducer
To dispatch an action on load, you can use a lifecycle method in a React component, such as componentDidMount(). This method is called once the component has mounted, allowing you to dispatch an action to the Redux store.

What is the difference between Flow and PropTypes?

  • Flow is a type checking tool for JavaScript, while PropTypes is a runtime type checking library
  • Flow and PropTypes are the same thing
  • PropTypes is a type checking tool for JavaScript, while Flow is a runtime type checking library
  • PropTypes is a runtime validation library for React components
The main difference between Flow and PropTypes is that Flow is a type checking tool for JavaScript that checks types at compile-time, while PropTypes is a runtime type checking library for React components that checks types at runtime. Flow is particularly useful in large codebases where it can be difficult to keep track of all the variables and function calls, while PropTypes is useful for catching errors in React components at runtime.

What is suspense component?

  • A component for handling errors in React
  • A component for delaying rendering in React
  • A component for handling lazy loading in React
  • A component for handling forms in React
The suspense component is a component for delaying rendering in React. The suspense component allows components to wait for asynchronous data to load before rendering, improving the user experience and reducing loading times. The suspense component is typically used with code splitting and lazy loading to enable on-demand loading of code.

Why ReactDOM is separated from React?

  • To improve performance and reduce bundle size
  • To provide a more modular architecture for React
  • To support different rendering targets, such as mobile devices or game engines
  • To support server-side rendering in Node.js
ReactDOM is separated from React in order to improve performance and reduce the bundle size of React applications. Separating the rendering logic from the component logic allows for more efficient updates and reduces the amount of JavaScript that needs to be downloaded by the client. This separation also allows for easier integration with other rendering targets, such as native mobile apps or desktop applications.