React Render Processing #shortsfeed #short #coding

In React, render processing refers to the way React handles rendering components to the DOM, including the lifecycle of rendering, re-rendering, and updating the UI efficiently. Here’s an overview of how React processes rendering:

1. Initial Render

• When a React component is first mounted, it undergoes an initial render.
• During this phase, React creates a virtual DOM (a lightweight copy of the actual DOM) based on the component’s structure.
• React then “diffs” the virtual DOM with the real DOM and only applies the changes needed to match the real DOM to the virtual DOM.

2. Re-render Triggered by State or Props Changes

• When a component’s state or props change, React re-renders that component to reflect the new state in the UI.
• React calls the render() function of the component to create a new virtual DOM.
• React compares the new virtual DOM with the previous virtual DOM to determine which parts of the actual DOM need to be updated.

3. Virtual DOM and Reconciliation

• React uses the virtual DOM to optimize rendering performance.
• During each render, React calculates the minimal number of changes required and applies only those changes to the actual DOM.
• This process, called “reconciliation,” reduces unnecessary updates, improving performance.

4. React Fiber (Concurrent Rendering)

• React Fiber is an internal engine that optimizes rendering for large applications by breaking rendering work into small units.
• Fiber enables React to pause and resume work, allowing it to handle more complex rendering tasks without blocking the main thread.
• With concurrent rendering, React can prioritize urgent updates, such as animations or user input, over other updates.

5. Batching and Optimizations

• React groups (or “batches”) multiple state updates and re-renders them together to avoid excessive renders.
• React’s useMemo and useCallback hooks allow you to optimize performance by memoizing values or functions, ensuring components only re-render when necessary.
• Lazy loading and code splitting in React also help load components or parts of components only when needed.

6. Render Lifecycle in Class Components and Function Components

• Class Components: Lifecycle methods like componentDidMount, shouldComponentUpdate, and componentDidUpdate control the render process.
• Function Components: The useEffect and useLayoutEffect hooks help manage side effects around rendering.

7. React Profiler

• React Profiler is a tool for measuring the performance of each component’s render cycle.
• It helps identify performance bottlenecks by showing render times and re-render counts.

By optimizing rendering through techniques like virtual DOM, reconciliation, Fiber, and batching, React efficiently manages updates, reducing the impact on UI performance and creating a smoother user experience. #shorts #shortsfeed #shortfeed