Vite Advanced Patterns

Advanced configuration for Vite 8 (Rolldown-powered, stable Mar 2026) with Environment API from Vite 7.

Vite 8: Rolldown-Powered Builds (Default)

Vite 8 replaces esbuild+Rollup with Rolldown (Rust-based unified bundler), delivering 7.7x faster builds and 50% less memory. This is now the default for all new projects.

npm install vite@8  # Direct upgrade

Key improvements:

Metric	Vite 7	Vite 8	Improvement
Build time (Linear)	46s	6s	7.7x faster
Dev server startup	~3s	~1s	3x faster
HMR updates	~100ms	~60ms	40% faster
Memory usage	~800MB	~400MB	50% reduction

Breaking changes from Vite 7:

• build.rollupOptions → build.rolldownOptions (auto-converted with deprecation warning)
• transformWithEsbuild → transformWithOxc
• Plugin transform() returning JS must add moduleType: 'js' to return value
• manualChunks object form removed — use function form or advancedChunks
• 'system' / 'amd' output formats no longer supported
• Lightning CSS is now standard (replaces esbuild for CSS minification)
• Browser target bump: Chrome 107→111, Firefox 104→114, Safari 16.0→16.4

advancedChunks (Replaces manualChunks)

Vite 8 introduces declarative chunk grouping with priority control and size constraints:

export default defineConfig({
  build: {
    rolldownOptions: {
      output: {
        advancedChunks: {
          groups: [
            { name: 'react-vendor', test: /[\\/]node_modules[\\/](react|react-dom)[\\/]/, priority: 20 },
            { name: 'ui-vendor', test: /[\\/]node_modules[\\/]@radix-ui[\\/]/, priority: 15, minShareCount: 2 },
            { name: 'vendor', test: /[\\/]node_modules[\\/]/, priority: 10, maxSize: 500000 },
          ],
        },
      },
    },
  },
})

Load Read("${CLAUDE_SKILL_DIR}/references/vite8-rolldown.md") for full migration options, benchmarks, advancedChunks syntax, Oxc benefits, and migration checklist.

Environment API (from Vite 7, stable)

Multi-environment support (client/SSR/edge) is first-class:

export default defineConfig({
  environments: {
    client: { build: { outDir: 'dist/client' } },
    ssr: { build: { outDir: 'dist/server', ssr: true } },
  },
});

Load Read("${CLAUDE_SKILL_DIR}/references/environment-api.md") for full configuration, per-environment plugins, Builder API, and buildApp hook.

Plugin Development

Hooks for config, transform, resolveId, load, virtual modules, HMR, and environment-aware transforms.

Load Read("${CLAUDE_SKILL_DIR}/references/plugin-development.md") for plugin structure, hook execution order, and advanced patterns.

SSR Configuration

Middleware mode for dev, separate client/server builds for prod, streaming SSR support.

Load Read("${CLAUDE_SKILL_DIR}/references/ssr-configuration.md") for entry points, dev/prod server setup, and streaming patterns.

Build Optimization

Chunk splitting with advancedChunks (Vite 8, preferred) or manualChunks (Vite 7 legacy), tree shaking, minification, and bundle analysis.

Load Read("${CLAUDE_SKILL_DIR}/references/chunk-optimization.md") for chunk strategies, build targets, and optimization checklist.

Quick Reference

Feature	Vite 8 Status
Rolldown bundler	Default (replaces esbuild+Rollup)
Environment API	Stable (from Vite 7)
ESM-only distribution	Default
Node.js requirement	20.19+ or 22.12+
advancedChunks	New (replaces manualChunks)
buildApp hook	Stable (for multi-env plugins)
createBuilder	Multi-env builds
Oxc integration	Parsing 3x faster than SWC

Key Decisions

Decision	Recommendation
New projects	Vite 8 (default)
Existing production apps	Evaluate Vite 8, use rolldown-vite for gradual migration
Multi-env builds	Environment API (environments config)
Plugin scope	Use this.environment for env-aware plugins
SSR	Middleware mode for dev, separate builds for prod
Chunks	advancedChunks for Vite 8, manualChunks for Vite 7 compat

Related Skills

• biome-linting - Fast linting alongside Vite
• ork:react-server-components-framework - SSR integration
• edge-computing-patterns - Edge environment builds
• ork:storybook-testing - Component testing with Vitest

References

Load on demand with Read("${CLAUDE_SKILL_DIR}/references/<file>"):

File	Content
vite8-rolldown.md	Rolldown migration, benchmarks, advancedChunks, Oxc benefits
environment-api.md	Multi-environment builds, Builder API, per-env plugins
plugin-development.md	Plugin hooks, virtual modules, HMR, env-aware transforms
ssr-configuration.md	Entry points, dev/prod servers, streaming SSR
library-mode.md	Building publishable npm packages
chunk-optimization.md	advancedChunks, manualChunks, tree shaking, bundle analysis