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⚠️ This article was written in 2020. Some content may be outdated.

Webpack 5 Asset Modules: Replacing file-loader

Webpack 5 Asset Modules, as a replacement for file-loader, are being used more and more widely in frontend development. Starting from real projects, this article takes a deep look at their core principles and best practices.

Basic Usage ​

In real projects, the usage gets a bit more involved:

javascript
import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import { resolve } from 'path'

export default defineConfig({
  plugins: [vue()],
  resolve: { alias: { '@': resolve(__dirname, 'src') } },
  server: {
    port: 3000,
    proxy: { '/api': { target: 'http://localhost:8080', changeOrigin: true } }
  },
  build: {
    rollupOptions: {
      output: {
        manualChunks: {
          vendor: ['vue', 'vue-router', 'vuex'],
          utils: ['lodash-es', 'dayjs']
        }
      }
    }
  }
})

This way, both the testability and extensibility of the code improve.

Advanced Usage ​

Here is a complete example:

javascript
module.exports = {
  entry: './src/index.js',
  output: { path: __dirname + '/dist', filename: '[name].[contenthash:8].js' },
  module: {
    rules: [
      { test: /\.jsx?$/, exclude: /node_modules/, use: 'babel-loader' },
      { test: /\.css$/, use: ['style-loader', 'css-loader', 'postcss-loader'] }
    ]
  },
  optimization: {
    splitChunks: {
      chunks: 'all',
      cacheGroups: {
        vendor: { test: /[\\/]node_modules[\\/]/, name: 'vendors' }
      }
    }
  }
}

Pay attention to edge-case handling — that is critical in production.

Practical Cases ​

The key is to understand the core logic:

javascript
import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import { resolve } from 'path'

export default defineConfig({
  plugins: [vue()],
  resolve: { alias: { '@': resolve(__dirname, 'src') } },
  server: {
    port: 3000,
    proxy: { '/api': { target: 'http://localhost:8080', changeOrigin: true } }
  },
  build: {
    rollupOptions: {
      output: {
        manualChunks: {
          vendor: ['vue', 'vue-router', 'vuex'],
          utils: ['lodash-es', 'dayjs']
        }
      }
    }
  }
})

Performance optimization has to be tied to the specific scenario; not every case needs over-optimization.

Performance Optimization ​

Here are some ways we can improve on this:

javascript
module.exports = {
  entry: './src/index.js',
  output: { path: __dirname + '/dist', filename: '[name].[contenthash:8].js' },
  module: {
    rules: [
      { test: /\.jsx?$/, exclude: /node_modules/, use: 'babel-loader' },
      { test: /\.css$/, use: ['style-loader', 'css-loader', 'postcss-loader'] }
    ]
  },
  optimization: {
    splitChunks: {
      chunks: 'all',
      cacheGroups: {
        vendor: { test: /[\\/]node_modules[\\/]/, name: 'vendors' }
      }
    }
  }
}

This approach has been running stably in production for over half a year and is proven in practice.

Summary ​

  • Before using it in production, make sure to verify compatibility.
  • In team collaboration, conventions and documentation matter more than the technology itself.
  • Keep an eye on the community; technical solutions need continuous iteration.
  • Don't adopt new tech just for the sake of using it.
  • Code examples are for reference only; adapt them to your business scenarios.

MIT Licensed