Q21. What is Virtual DOM?
The _Virtual DOM_ (VDOM) is a lightweight, in-memory representation of _Real DOM_ used by libraries like React to optimize UI rendering. The representation of a UI is kep...
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Q22. How Virtual DOM works?
The _Virtual DOM_ works in five simple steps. **1. Initial Render** When a UI component renders for the first time, it returns JSX. React uses this structure to create a ...
Q23. What is the difference between Shadow DOM and Virtual DOM?
The _Shadow DOM_ is a browser technology designed primarily for scoping variables and CSS in _web components_. The _Virtual DOM_ is a concept implemented by libraries in ...
Q24. What is React Fiber?
**React Fiber** is the **new reconciliation engine** in React, introduced in React 16. It’s a complete rewrite of React’s core algorithm(old stack-based algorithm) for re...
Q25. What is the main goal of React Fiber?
The goal of _React Fiber_ is to increase its suitability for areas like animation, layout, and gestures. Its headline feature is **incremental rendering**: the ability to...
Q26. What are controlled components?
A **controlled component** is a React component that **fully manages the form element's state**(e.g, elements like ``, ``, or ``)) using React's internal state mechanism....
Q27. What are uncontrolled components?
The **Uncontrolled components** are form elements (like ``, ``, or ``) that **manage their own state internally** via the **DOM**, rather than through React state. You ca...
Q28. What is the difference between createElement and cloneElement?
Both `React.createElement` and `React.cloneElement` are used to work with React elements, but they serve different purposes. #### **createElement:** Creates a new React e...
Q29. What is Lifting State Up in React?
When several components need to share the same changing data then it is recommended to _lift the shared state up_ to their closest common ancestor. That means if two chil...
Q30. What are Higher-Order Components?
A _higher-order component_ (_HOC_) is a function that takes a component and returns a new enhanced component with additional props, behavior, or data. It’s a design patte...