11.Code_Splitting.md

100 React Questions (Code Splitting)

Q1. What is Code Splitting in React? V. IMP.

Code splitting is a technique to split the JavaScript bundle into smaller chunks, which are loaded on-demand.

Q2. How to Implement Code Splitting in React? V. IMP.

• Use React.lazy() to lazily import components.

• Wrap components with Suspense to handle loading.

• Configure your build tool (e.g., Webpack) for dynamic imports.

  const CodeSplit = () => {
  return <div>My component!</div>;
  };
  
  export default CodeSplit;

  App.js

  import React, { lazy, Suspense } from "react";
  
  const CodeSplit = lazy(() => import("./Others/CodeSplit"));
  
  function App() {
  return (
      <div>
      <Suspense fallback={<div>Loading...</div>}>
          <CodeSplit />
      </Suspense>
      </div>
  );
  }

  webpack installation command

  // npm install webpack webpack-cli --save-dev
  const path = require('path');
  
  module.exports = {
  // other webpack configuration...
  output: {
      filename: '[name].bundle.js',
      path: path.resolve(__dirname, 'dist'),
  },
  };

Q3. What is the role of Lazy and Suspense methods in React? V. IMP.

• React.lazy is a function that allows you to load a component lazily.

• It enables code splitting by allowing you to import a component asynchronously/dynamically, meaning the component is loaded only when needed.

• The Suspense component is used to display a fallback UI while the lazily loaded component is being fetched.

App.js

import React, { lazy, Suspense } from "react";

const CodeSplit = lazy(() => import("./Others/CodeSplit"));

function App() {
return (
    <div>
    <Suspense fallback={<div>Loading...</div>}>
        <CodeSplit />
    </Suspense>
    </div>
);
}

Q4. What are the Pros and Cons of Code Splitting?

Pros:

Pros of Code Splitting	Description
Faster Initial Load Time	Code splitting reduces the initial load time of your application by only loading the necessary code for the current view or feature. Good for performance.
Optimized Bandwidth Usage	By loading only the code needed for a specific page, it reduces the amount of data transferred over the network. Good for slow networks.
Improved Caching	Smaller, more focused code chunks are more likely to be cached by the browser.
Parallel Loading	Multiple smaller chunks can be loaded simultaneously, leading to faster overall loading times.
Easier Maintenance	Code splitting can make your codebase more modular, independent, and easier to maintain.

Cons:

Cons of Code Splitting	Description
Complexity	Implementing code splitting introduces additional complexity to your application. This complexity can make the development process slow.
Tooling Dependencies	Proper code splitting often requires specific build tools and configurations, such as Webpack and Babel. Managing these tools is challenging.
Potential for Runtime Errors	Dynamically loading code at runtime can introduce the possibility of runtime errors. Careful testing is necessary to catch such issues.
Increased Number of Requests	Code splitting may increase the number of HTTP requests needed to fetch all the necessary chunks. This can impact performance.
Learning Curve	Developers who are new to code splitting may need time to understand the concepts and best practices. This can be a challenging.

Q5. What is the role of the import() function in code splitting?

The import() function returns a promise that allow dyanmic loading of modules.

App.js

import React, { lazy, Suspense } from "react";

const CodeSplit = lazy(() => import("./Others/CodeSplit"));

function App() {
return (
    <div>
    <Suspense fallback={<div>Loading...</div>}>
        <CodeSplit />
    </Suspense>
    </div>
);
}

Q6. What is the purpose of the fallback prop in Suspense?

The fallback prop provides a loading indicator or UI while the dynamically imported component is being loaded.

Q7. Can you dynamically load CSS files using code splitting in React?

Yes, using dynamic import() for CSS files allows you to load styles on-demand along with the corresponding components.

Q8. How do you inspect and analyze the generated chunks in a React application?

Use tools like Webpack Bundle Analyzer to analyze the size and composition of chunks.