How to optimize performance in Module Federation? What are the best practices? - 面试题

Performance optimization for Module Federation can be approached from multiple dimensions. Here are detailed optimization strategies:

1. Build Artifact Optimization

Code Splitting:

javascript
// Remote application configuration
new ModuleFederationPlugin({
  name: 'remoteApp',
  filename: 'remoteEntry.js',
  exposes: {
    './Button': './src/Button',
    './Modal': './src/Modal'
  },
  // Fine-grained exposure, avoid packaging unnecessary content
  splitChunks: {
    chunks: 'all',
    cacheGroups: {
      vendor: {
        test: /[\\/]node_modules[\\/]/,
        name: 'vendors',
        priority: 10
      }
    }
  }
})

Tree Shaking:

Ensure using ES Module syntax
Set "sideEffects": false in package.json
Avoid using CommonJS require

2. Loading Performance Optimization

Preload Critical Modules:

javascript
// Preload during application idle time
const preloadRemoteModule = () => {
  if ('requestIdleCallback' in window) {
    requestIdleCallback(() => {
      import('remoteApp/HeavyComponent')
    })
  }
}

// Or use link tag for preloading
const link = document.createElement('link')
link.rel = 'preload'
link.href = 'http://localhost:3001/remoteEntry.js'
link.as = 'script'
document.head.appendChild(link)

CDN Deployment:

Deploy remoteEntry.js and module files to CDN
Use HTTP/2 or HTTP/3 for accelerated transmission
Configure reasonable cache strategy (Cache-Control: max-age=31536000)

3. Runtime Optimization

Shared Dependency Optimization:

javascript
shared: {
  react: {
    singleton: true,
    requiredVersion: deps.react,
    eager: false, // Avoid eager loading
    strictVersion: false // Allow version mismatch
  }
}

Lazy Loading Strategy:

javascript
// Use React.lazy and Suspense
const RemoteComponent = React.lazy(() => 
  import('remoteApp/Component')
)

// Or use dynamic import
const loadModule = async () => {
  const module = await import('remoteApp/Module')
  return module.default
}

4. Cache Strategy

Versioned Filenames:

javascript
// Webpack configuration
output: {
  filename: '[name].[contenthash].js',
  chunkFilename: '[name].[contenthash].js'
}

Service Worker Caching:

javascript
// Cache remoteEntry.js
workbox.routing.registerRoute(
  /.*remoteEntry\.js/,
  new workbox.strategies.NetworkFirst({
    cacheName: 'remote-entries',
    plugins: [
      new workbox.expiration.ExpirationPlugin({
        maxEntries: 10,
        maxAgeSeconds: 7 * 24 * 60 * 60
      })
    ]
  })
)

5. Monitoring and Diagnostics

Performance Monitoring:

javascript
// Monitor module loading time
const loadRemoteModule = async (moduleName) => {
  const startTime = performance.now()
  try {
    const module = await import(moduleName)
    const loadTime = performance.now() - startTime
    console.log(`${moduleName} loaded in ${loadTime}ms`)
    return module
  } catch (error) {
    console.error(`Failed to load ${moduleName}:`, error)
    throw error
  }
}

6. Best Practices

Expose on demand: Only expose necessary modules, avoid packaging unrelated code
Version control: Use semantic versioning to ensure compatibility
Error boundaries: Add error boundaries for remote modules to avoid affecting the entire application
Fallback strategy: Prepare local fallback components to handle remote loading failures
Progressive loading: Prioritize loading core features, delay loading secondary features

Performance Metrics:

First Contentful Paint (FCP) < 1.8s
Largest Contentful Paint (LCP) < 2.5s
Cumulative Layout Shift (CLS) < 0.1
First Input Delay (FID) < 100ms

Through these optimization strategies, the performance of Module Federation applications can be significantly improved.