Vite 8.1: Introducing Bundled Dev Mode ⚡️
Vite 8.1 adds experimental dev-mode bundling, Chunk Import Map, native Wasm imports, and Lightning CSS improvements.
The Vite team has shipped release 8.1. The main event is the experimental Bundled Dev Mode.
What’s the idea?
Vite’s historical unbundled approach, serving files to the browser “as is” through native ESM imports, is ideal for small projects but starts slowing down at huge scales. When an application grows to thousands of modules, the browser chokes on the number of HTTP requests.
Thanks to the move to the fast Rust bundler Rolldown, Vite can now bundle modules together on the fly during development.
What this gives you:
- Speed: In tests with 10,000 React components, cold starts became 15 times faster and page reloads 10 times faster, while network requests dropped by an order of magnitude.
- Stable HMR: Hot module replacement stays instant regardless of the size of the codebase.
- Matching environments: Development mode is now as close to production as possible, eliminating differences in code behavior.
You can enable it in vite.config.js with experimental.bundledDev: true, or launch with the --experimental-bundle flag.
What else is in the release:
- Experimental Chunk Import Map: A caching optimization. Thanks to native Import Maps, changing code in one file no longer triggers cascading hash invalidation across the entire import chain.
- Native Wasm ESM: You can now import
.wasmfiles directly without third-party plugins:import { add } from './add.wasm'. - Lightning CSS: They’ve implemented the missing features needed to move away from PostCSS. In the next major release, they plan to make Lightning CSS the default processor.