React.js is one of the most common topics in front-end interviews, and understanding its internal working helps you stand out. So, how would you explain React’s working principle in an interview setting?
For example, you could talk about how React uses a virtual DOM to efficiently update the user interface. When the state of a component changes, React creates a lightweight copy of the real DOM called the virtual DOM.
It then compares this virtual DOM to the previous version using a process called reconciliation. Only the parts of the DOM that have changed are updated in the browser, improving performance and minimizing costly re-rendering.
You can also mention components, props, and hooks, explaining how React encourages a declarative and component-based architecture that simplifies UI development and state management.
So, how would you describe how React works in an interview?
React works by using a virtual DOM to efficiently manage updates to the real DOM.
When a component’s state changes, React creates a new virtual DOM tree, compares it with the previous one using a process called diffing, and updates only the changed parts in the actual DOM.
This makes UI updates fast and efficient. React also uses components, props, and state to build reusable, declarative user interfaces.
To thoroughly prepare for the interview for React, follow this resource. Top 101 React Interview Questions [2024]
All the best 
React is a component-based JavaScript library that uses a virtual DOM to optimize rendering. When data changes, React doesn’t update the entire DOM.
Instead, it builds a virtual copy, compares it with the previous version (reconciliation), and updates only the affected nodes.
Components manage their own state and receive props for data sharing. Hooks like useState and useEffect allow functional components to handle logic and lifecycle events, making React apps fast, maintainable, and predictable.
React’s core mechanism revolves around its virtual DOM and reconciliation algorithm. When state or props change, React creates a virtual DOM tree and performs a diffing process to detect minimal changes.
Then, through fiber architecture, it schedules and batches DOM updates efficiently, ensuring smooth UI rendering even for complex applications.
React promotes a unidirectional data flow using props, state, and context, while hooks provide a powerful, declarative way to handle side effects and lifecycle management in functional components.