React JS Interview Questions

• What is React?
• What are the major features of React?
• What is JSX?
• What is the difference between Element and Component?
• How to create components in React?
• When to use a Class Component over a Function Component?
• What are Pure Components?
• What is state in React?
• What are props in React?
• What is the difference between state and props?
• Why should we not update the state directly?
• What is the purpose of callback function as an argument of setState()?
• What is the difference between HTML and React event handling?
• How to bind methods or event handlers in JSX callbacks?
• How to pass a parameter to an event handler or callback?
• What are synthetic events in React?
• What are inline conditional expressions?
• What is "key" prop and what is the benefit of using it in arrays of elements?
• What is the use of refs?
• How to create refs?
• What are forward refs?
• Which is preferred option with in callback refs and findDOMNode()?
• Why are String Refs legacy?
• What is Virtual DOM?
• How Virtual DOM works?
• What is the difference between Shadow DOM and Virtual DOM?
• What is React Fiber?
• What is the main goal of React Fiber?
• What are controlled components?
• What are uncontrolled components?
• What is the difference between createElement and cloneElement?
• What is Lifting State Up in React?
• What are the different phases of component lifecycle?
• What are the lifecycle methods of React?
• What are Higher-Order components?
• How to create props proxy for HOC component?
• What is context?
• What is children prop?
• How to write comments in React?
• What is the purpose of using super constructor with props argument?
• What is reconciliation?
• How to set state with a dynamic key name?
• What would be the common mistake of function being called every time the component renders?
• Is lazy function supports named exports?
• Why React uses className over class attribute?
• What are fragments?
• Why fragments are better than container divs?
• What are portals in React?
• What are stateless components?
• What are stateful components?
• How to apply validation on props in React?
• What are the advantages of React?
• What are the limitations of React?
• What are error boundaries in React v16
• How error boundaries handled in React v15?
• What are the recommended ways for static type checking?
• What is the use of react-dom package?
• What is the purpose of render method of react-dom?
• What is ReactDOMServer?
• How to use InnerHtml in React?
• How to use styles in React?
• How events are different in React?
• What will happen if you use setState in constructor?
• What is the impact of indexes as keys?
• Is it good to use setState() in componentWillMount() method?
• What will happen if you use props in initial state?
• How do you conditionally render components?
• Why we need to be careful when spreading props on DOM elements??
• How you use decorators in React?
• How do you memoize a component?
• How you implement Server-Side Rendering or SSR?
• How to enable production mode in React?
• What is CRA and its benefits?
• What is the lifecycle methods order in mounting?
• What are the lifecycle methods going to be deprecated in React v16?
• What is the purpose of getDerivedStateFromProps() lifecycle method?
• What is the purpose of getSnapshotBeforeUpdate() lifecycle method?
• Do Hooks replace render props and higher order components?
• What is the recommended way for naming components?
• What is the recommended ordering of methods in component class?
• What is a switching component?
• Why we need to pass a function to setState()?
• What is strict mode in React?
• What are React Mixins?
• Why is isMounted() an anti-pattern and what is the proper solution?
• What are the Pointer Events supported in React?
• Why should component names start with capital letter?
• Are custom DOM attributes supported in React v16?
• What is the difference between constructor and getInitialState?
• Can you force a component to re-render without calling setState?
• What is the difference between super() and super(props) in React using ES6 classes?
• How to loop inside JSX?
• How do you access props in attribute quotes?
• What is React PropType array with shape?
• How to conditionally apply class attributes?
• What is the difference between React and ReactDOM?
• Why ReactDOM is separated from React?
• How to use React label element?
• How to combine multiple inline style objects?
• How to re-render the view when the browser is resized?

Disclaimer : This content may be copyrighted because I have written this blog by searching internet and talking to experienced persons.