Code Splitting Chunk Load Error Fix

In this tutorial, you'll learn about Code Splitting Chunk Load Error Fix. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

Your app shows ChunkLoadError: Loading chunk X failed — a dynamically imported module failed to load because the chunk file is missing, the URL is wrong, or the server returned a 404.

Step-by-Step Fix

1. Check the chunk URL in the error

Error: Loading chunk 3 failed.
(error: https://example.com/js/3.abc123.chunk.js)

Check if the chunk file exists at that URL:

curl -I https://example.com/js/3.abc123.chunk.js

Expected on success: HTTP/2 200. On failure: HTTP/2 404.

2. Fix Webpack output configuration

// Wrong — chunk filename not configured
module.exports = {
  output: {
    filename: "bundle.js",
    path: path.resolve(__dirname, "dist"),
  },
  // Chunks use default names with content hash
};

// Right — configure chunk filename explicitly
module.exports = {
  output: {
    filename: "[name].[contenthash].js",
    chunkFilename: "[name].[contenthash].chunk.js",
    path: path.resolve(__dirname, "dist"),
    publicPath: "/js/",  // Ensure this matches the server path
  },
};

3. Fix dynamic import with proper error handling

// Wrong — no error handling for chunk load failure
const module = await import("./heavyComponent.jsx");

// Right — catch and retry chunk load failures
async function loadComponent() {
  try {
    const module = await import("./heavyComponent.jsx");
    return module.default;
  } catch (err) {
    if (err.name === "ChunkLoadError") {
      // Force reload the page to get latest chunks
      window.location.reload();
    }
    throw err;
  }
}

4. Ensure chunks are deployed with the app

# Wrong — only deploying the main bundle
rsync -avz dist/index.html dist/main.*.js user@server:/var/www/app/

# Right — deploy all chunks
rsync -avz dist/ user@server:/var/www/app/

Common Mistakes

Prevention

• Deploy the entire build output directory — never pick and choose files.
• Use content hashes in chunk filenames for cache busting.
• Set output.publicPath correctly for CDN deployments.
• Implement chunk load error retry and fallback UI.
• Test chunk loading with network throttling in DevTools.

DodaTech Tools

Doda Browser's network inspector shows chunk loading failures with full request details for debugging. DodaZIP compresses and caches chunk archives for faster redeployments. Durga Antivirus Pro uses Code Splitting to load only the security module needed for each scan.

Common Mistakes with splitting error

1. Misunderstanding that String is [Char] with poor performance for large text operations
2. Using foldl instead of foldl' causing stack overflow on large lists
3. Forgetting deriving (Show, Eq) on custom data types needed for debugging

These mistakes appear frequently in real-world CODE code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ