React is a JavaScript library developed by Facebook for building user interfaces using reusable components and a virtual DOM for efficient rendering.

What are React hooks?

Hooks are functions that allow you to use state and lifecycle features in functional components. Common hooks include useState, useEffect, useContext, and useReducer.

What is the virtual DOM?

The virtual DOM is an in-memory representation of the real DOM. React uses it to determine what changes need to be made and updates only those parts in the actual DOM efficiently.

React.js Interview Questions

71. What is StrictMode in React?

72. Why does StrictMode intentionally double-render components in development?

73. What are concurrent features in React?

74. What is concurrent rendering?

75. How does React scheduling work internally?

76. What is Suspense in React?

77. How does Suspense improve asynchronous UI handling?

78. What are lazy-loaded components?

79. How does React.lazy work?

80. What are code-splitting strategies in React?