What is the virtual DOM in React?

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The Virtual DOM (VDOM) in React is a lightweight, in-memory representation of the real DOM that helps React update the UI efficiently.

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🔑 Key Points:

1. Why Virtual DOM?

   • Direct manipulation of the real DOM is slow.

   • Virtual DOM allows React to minimize costly DOM operations by updating only what’s necessary.

2. How It Works:

   1. React maintains a virtual copy of the UI (VDOM).

   2. When the state or props of a component change, React creates a new virtual DOM tree.

   3. React diffs the new VDOM with the previous VDOM (called reconciliation) to find the minimal changes.

   4. Only the differences are applied to the real DOM, improving performance.

3. Benefits:

   • Faster updates and rendering.

   • Efficient for large and complex UIs.

   • Keeps UI in sync with application state.

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🔹 Example Conceptually:

• Current state: <h1>Hello</h1>

• New state: <h1>Hello, World!</h1>

• Virtual DOM calculates that only the text node changed, so only that part is updated in the real DOM.

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✅ In short:
The virtual DOM in React is a lightweight copy of the real DOM that allows React to update the UI efficiently by changing only what’s necessary.

I can also make a simple diagram showing the flow between Virtual DOM, diffing, and Real DOM updates if you want.

Read More

What is a React component?

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