Browser support and compatibility strategy

Author：Chuan Chen 阅读数：4941人阅读分类：构建工具

Browser Support

Vite.js natively supports modern browsers, including Chrome >=87, Firefox >=78, Safari >=13, and Edge >=88. These browsers have native support for ES modules, which is a core feature of Vite's development environment. For production builds, Vite uses Rollup for bundling and generates code compatible with modern browsers by default.

Support for older browsers can be added via the @vitejs/plugin-legacy plugin. This plugin automatically generates legacy-format code (such as SystemJS or UMD) and corresponding polyfills. Example configuration:

// vite.config.js
import legacy from '@vitejs/plugin-legacy'

export default {
  plugins: [
    legacy({
      targets: ['defaults', 'not IE 11'],
      additionalLegacyPolyfills: ['regenerator-runtime/runtime']
    })
  ]
}

Compatibility Strategy

Development Environment Strategy

In the development environment, Vite leverages native browser ES module support for fast startup and unbundled development. Special attention is required in the following cases:

Bare Module Imports: Vite automatically rewrites bare module imports (e.g., import vue from 'vue').
CSS Preprocessors: Ensure the corresponding preprocessor (e.g., sass) is installed in the development environment.
Web Workers: Automatically handled when imported with the ?worker suffix.

// Worker usage specific to the development environment
import Worker from './worker.js?worker'
const worker = new Worker()

Production Environment Strategy

For production builds, Vite adopts a different compatibility approach:

Code Splitting: Automatically handles dynamic imports.
Asset Handling: Resources smaller than 4KB are inlined as base64.
CSS Handling: CSS is automatically extracted and minified.

Target browsers can be explicitly specified via configuration:

// vite.config.js
export default {
  build: {
    target: ['es2015', 'chrome58', 'firefox57', 'safari11']
  }
}

Polyfill Handling

Vite does not automatically inject polyfills; manual handling is required for compatibility issues. The following two approaches are recommended:

Using Polyfill.io: Dynamically loads required polyfills.
Manual Import: Import specific polyfills at the top of the entry file.

<!-- Using Polyfill.io in index.html -->
<head>
  <script src="https://polyfill.io/v3/polyfill.min.js?features=es2015%2Ces2016%2Ces2017"></script>
</head>

For core functionality polyfills, configure in vite.config.js:

export default {
  optimizeDeps: {
    include: ['core-js/stable', 'regenerator-runtime/runtime']
  }
}

CSS Compatibility Handling

Vite has built-in PostCSS support, which can handle CSS compatibility via configuration:

Autoprefixing: Use autoprefixer.
CSS Fallbacks: Use postcss-preset-env.

// postcss.config.js
module.exports = {
  plugins: [
    require('postcss-preset-env')({
      stage: 3,
      features: {
        'nesting-rules': true
      }
    }),
    require('autoprefixer')
  ]
}

Environment Variable Compatibility

Vite uses import.meta.env instead of process.env, which may cause incompatibility with older toolchains. Solutions:

Configure the define Option: Replace global variables.
Use Compatibility Plugins: Transform syntax.

// vite.config.js
export default {
  define: {
    'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV)
  }
}

Third-Party Library Compatibility Issues

Some legacy libraries may require special handling:

CommonJS Dependencies: Vite automatically converts most CommonJS modules.
Global Variable Dependencies: Explicit configuration is required.

// vite.config.js
export default {
  optimizeDeps: {
    include: ['jquery'],
    exclude: ['vue-demi']
  }
}

For particularly troublesome libraries, create custom plugins:

// vite.config.js
export default {
  plugins: [{
    name: 'custom-legacy-plugin',
    transform(code, id) {
      if (id.includes('legacy-library')) {
        return transformLegacyCode(code)
      }
    }
  }]
}

Testing Strategy

A comprehensive testing plan is required to ensure compatibility:

Unit Testing: Use Jest or Vitest.
E2E Testing: Use Cypress or Playwright.
Cross-Browser Testing: Use BrowserStack or Sauce Labs.

Configuration example:

// vitest.config.js
import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    environment: 'jsdom',
    coverage: {
      provider: 'istanbul'
    }
  }
})

Build Target Configuration

Vite supports fine-grained control over build output:

// vite.config.js
export default {
  build: {
    target: 'esnext',
    polyfillModulePreload: true,
    cssTarget: 'chrome61'
  }
}

For special requirements, configure multiple entry points:

export default {
  build: {
    rollupOptions: {
      input: {
        main: 'index.html',
        legacy: 'legacy.html'
      }
    }
  }
}

Progressive Enhancement Strategy

A progressive enhancement approach is recommended:

Feature Detection: Dynamically load polyfills.
Conditional Loading: Load different resources based on browser capabilities.

Implementation example:

// Dynamically load polyfills
if (!('fetch' in window)) {
  import('whatwg-fetch').then(() => initApp())
} else {
  initApp()
}

Performance Optimization Considerations

Compatibility handling must account for performance impact:

On-Demand Polyfills: Avoid full imports.
Code Splitting: Separate modern and legacy code.
Resource Preloading: Optimize load order.

Configuration example:

export default {
  build: {
    rollupOptions: {
      output: {
        manualChunks(id) {
          if (id.includes('node_modules')) {
            return 'vendor'
          }
        }
      }
    }
  }
}

Error Handling Mechanism

A robust compatibility solution requires error handling:

Global Error Capture: window.onerror.
Resource Load Failures: Listen for error events.
Graceful Degradation: Provide fallback solutions.

Implementation example:

// Global error handling
window.addEventListener('error', (event) => {
  if (event.message.includes('SyntaxError')) {
    redirectToLegacyVersion()
  }
})

Continuous Integration Plan

Automate compatibility validation:

Multi-Browser Testing: Integrate into CI workflows.
Build Validation: Check output compatibility.
Performance Benchmarks: Monitor compatibility costs.

GitHub Actions example:

name: Cross-browser Test
on: [push]
jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        browser: [chrome, firefox, safari]
    steps:
      - uses: actions/checkout@v2
      - run: npm install
      - run: npm test -- --browser ${{ matrix.browser }}