What are the build optimization strategies in Rspack?

Rspack's build optimization is the core of its high performance. Through various optimization strategies, build speed and output quality can be further improved. Here's a detailed explanation of Rspack's build optimization:

Build Optimization Strategies

1. Incremental Builds

Incremental builds only rebuild changed modules, significantly improving build speed:

javascript
module.exports = {
  cache: {
    type: 'filesystem',
    cacheDirectory: path.resolve(__dirname, '.rspack-cache'),
    buildDependencies: {
      config: [__filename]
    }
  }
}

Optimization Points:

• Enable filesystem cache
• Configure cache directory
• Specify build dependencies

2. Parallel Processing

Rspack utilizes multi-core CPU to process build tasks in parallel:

javascript
module.exports = {
  parallelism: 4 // Set parallelism level
}

Optimization Recommendations:

• Set parallelism based on CPU core count
• Avoid excessive parallelism causing resource contention
• Monitor system resource usage

3. Module Resolution Optimization

Optimize module resolution paths to reduce file system access:

javascript
module.exports = {
  resolve: {
    modules: [path.resolve(__dirname, 'src'), 'node_modules'],
    extensions: ['.js', '.jsx', '.ts', '.tsx', '.json'],
    alias: {
      '@': path.resolve(__dirname, 'src'),
      '@components': path.resolve(__dirname, 'src/components'),
      '@utils': path.resolve(__dirname, 'src/utils')
    },
    symlinks: false,
    cacheWithContext: true
  }
}

Optimization Points:

• Use aliases to simplify import paths
• Explicitly specify extensions
• Disable symlink resolution

4. Code Splitting Optimization

Intelligently split code to optimize load performance:

javascript
module.exports = {
  optimization: {
    splitChunks: {
      chunks: 'all',
      minSize: 20000,
      maxSize: 244000,
      minChunks: 1,
      maxAsyncRequests: 30,
      maxInitialRequests: 30,
      automaticNameDelimiter: '~',
      cacheGroups: {
        vendors: {
          test: /[\\/]node_modules[\\/]/,
          priority: -10,
          reuseExistingChunk: true
        },
        default: {
          minChunks: 2,
          priority: -20,
          reuseExistingChunk: true
        }
      }
    }
  }
}

5. Tree Shaking Optimization

Remove unused code to reduce bundle size:

javascript
module.exports = {
  optimization: {
    usedExports: true,
    sideEffects: true,
    providedExports: true
  }
}

Optimization Points:

• Use ES Module syntax
• Correctly configure side effects
• Analyze build results

6. Minification Optimization

Use efficient minification tools:

javascript
const TerserPlugin = require('terser-webpack-plugin');

module.exports = {
  optimization: {
    minimize: true,
    minimizer: [
      new TerserPlugin({
        parallel: true,
        terserOptions: {
          compress: {
            drop_console: true,
            drop_debugger: true
          },
          format: {
            comments: false
          }
        },
        extractComments: false
      })
    ]
  }
}

Performance Monitoring

1. Build Time Analysis

javascript
const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');

module.exports = {
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'static',
      openAnalyzer: false,
      reportFilename: 'bundle-report.html'
    })
  ]
}

2. Build Performance Analysis

javascript
const { StatsWriterPlugin } = require('stats-webpack-plugin');

module.exports = {
  plugins: [
    new StatsWriterPlugin({
      filename: 'stats.json',
      stats: {
        all: true,
        timings: true,
        builtAt: true,
        assets: true,
        chunks: true,
        modules: true
      }
    })
  ]
}

Memory Optimization

1. Reduce Memory Usage

javascript
module.exports = {
  optimization: {
    runtimeChunk: 'single',
    removeAvailableModules: false,
    removeEmptyChunks: false,
    splitChunks: false
  }
}

2. Optimize Dependencies

javascript
module.exports = {
  externals: {
    react: 'React',
    'react-dom': 'ReactDOM'
  }
}

Development Environment Optimization

1. Fast Refresh

javascript
module.exports = {
  mode: 'development',
  devtool: 'eval-cheap-module-source-map',
  devServer: {
    hot: true,
    client: {
      overlay: {
        errors: true,
        warnings: false
      }
    }
  }
}

2. Reduce Build Content

javascript
module.exports = {
  mode: 'development',
  optimization: {
    removeAvailableModules: false,
    removeEmptyChunks: false,
    splitChunks: false
  }
}

Production Environment Optimization

1. Complete Optimization

javascript
module.exports = {
  mode: 'production',
  devtool: 'source-map',
  optimization: {
    minimize: true,
    moduleIds: 'deterministic',
    runtimeChunk: 'single',
    splitChunks: {
      chunks: 'all',
      cacheGroups: {
        vendor: {
          test: /[\\/]node_modules[\\/]/,
          name: 'vendors',
          chunks: 'all'
        }
      }
    }
  }
}

2. Asset Optimization

javascript
const ImageMinimizerPlugin = require('image-minimizer-webpack-plugin');

module.exports = {
  module: {
    rules: [
      {
        test: /\.(jpe?g|png|gif|svg)$/i,
        type: 'asset',
        parser: {
          dataUrlCondition: {
            maxSize: 8192
          }
        }
      }
    ]
  },
  optimization: {
    minimizer: [
      new ImageMinimizerPlugin({
        minimizer: {
          implementation: ImageMinimizerPlugin.imageminGenerate,
          options: {
            plugins: [
              ['imagemin-gifsicle', { interlaced: true }],
              ['imagemin-mozjpeg', { progressive: true }],
              ['imagemin-pngquant', { quality: [0.65, 0.9] }]
            ]
          }
        }
      })
    ]
  }
}

Best Practices

1. Environment Separation:

   • Development environment: Fast builds, complete source maps
   • Production environment: Complete optimization, minified code

2. Caching Strategy:

   • Use filesystem cache
   • Configure reasonable caching strategy
   • Regularly clean cache

3. Performance Monitoring:

   • Regularly analyze build performance
   • Identify performance bottlenecks
   • Continuously optimize

4. Dependency Management:

   • Reduce unnecessary dependencies
   • Use lightweight alternatives
   • Optimize third-party library usage

5. Code Quality:

   • Write optimizable code
   • Avoid over-optimization
   • Maintain code readability

Rspack's build optimization through the combination of various strategies can significantly improve build speed and output quality, providing developers with a more efficient development experience.