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Migration from v4

Node.js Support

Vite no longer supports Node.js 14 / 16 / 17 / 19, which reached its EOL. Node.js 18 / 20+ is now required.

Rollup 4

Vite is now using Rollup 4 which also brings along its breaking changes, in particular:

  • Import assertions (assertions prop) has been renamed to import attributes (attributes prop).
  • Acorn plugins are no longer supported.
  • For Vite plugins, this.resolve skipSelf option is now true by default.
  • For Vite plugins, this.parse now only supports the allowReturnOutsideFunction option for now.

Read the full breaking changes in Rollup's release notes for build-related changes in build.rollupOptions.

Deprecate CJS Node API

The CJS Node API of Vite is deprecated. When calling require('vite'), a deprecation warning is now logged. You should update your files or frameworks to import the ESM build of Vite instead.

In a basic Vite project, make sure:

  1. The vite.config.js file content is using the ESM syntax.
  2. The closest package.json file has "type": "module", or use the .mjs extension, e.g. vite.config.mjs.

For other projects, there are a few general approaches:

  • Configure ESM as default, opt-in to CJS if needed: Add "type": "module" in the project package.json. All *.js files are now interpreted as ESM and needs to use the ESM syntax. You can rename a file with the .cjs extension to keep using CJS instead.
  • Keep CJS as default, opt-in to ESM if needed: If the project package.json does not have "type": "module", all *.js files are interpreted as CJS. You can rename a file with the .mjs extension to use ESM instead.
  • Dynamically import Vite: If you need to keep using CJS, you can dynamically import Vite using import('vite') instead. This requires your code to be written in an async context, but should still be manageable as Vite's API is mostly asynchronous.

See the troubleshooting guide for more information.

Rework define and import.meta.env.* replacement strategy

In Vite 4, the define and import.meta.env.* features use different replacement strategies in dev and build:

  • In dev, both features are injected as global variables to globalThis and import.meta respectively.
  • In build, both features are statically replaced with a regex.

This results in a dev and build inconsistency when trying to access the variables, and sometimes even caused failed builds. For example:

// vite.config.js
export default defineConfig({
  define: {
    __APP_VERSION__: JSON.stringify('1.0.0'),
  },
})
const data = { __APP_VERSION__ }
// dev: { __APP_VERSION__: "1.0.0" } ✅
// build: { "1.0.0" } ❌

const docs = 'I like import.meta.env.MODE'
// dev: "I like import.meta.env.MODE" ✅
// build: "I like "production"" ❌

Vite 5 fixes this by using esbuild to handle the replacements in builds, aligning with the dev behaviour.

This change should not affect most setups, as it's already documented that define values should follow esbuild's syntax:

To be consistent with esbuild behavior, expressions must either be a JSON object (null, boolean, number, string, array, or object) or a single identifier.

However, if you prefer to keep statically replacing values directly, you can use @rollup/plugin-replace.

General Changes

SSR externalized modules value now matches production

In Vite 4, SSR externalized modules are wrapped with .default and .__esModule handling for better interoperability, but it doesn't match the production behaviour when loaded by the runtime environment (e.g. Node.js), causing hard-to-catch inconsistencies. By default, all direct project dependencies are SSR externalized.

Vite 5 now removes the .default and .__esModule handling to match the production behaviour. In practice, this shouldn't affect properly-packaged dependencies, but if you encounter new issues loading modules, you can try these refactors:

// Before:
import { foo } from 'bar'

// After:
import _bar from 'bar'
const { foo } = _bar
// Before:
import foo from 'bar'

// After:
import * as _foo from 'bar'
const foo = _foo.default

Note that these changes matches the Node.js behaviour, so you can also run the imports in Node.js to test it out. If you prefer to stick with the previous behaviour, you can set legacy.proxySsrExternalModules to true.

worker.plugins is now a function

In Vite 4, worker.plugins accepted an array of plugins ((Plugin | Plugin[])[]). From Vite 5, it needs to be configured as a function that returns an array of plugins (() => (Plugin | Plugin[])[]). This change is required so parallel worker builds run more consistently and predictably.

Allow path containing . to fallback to index.html

In Vite 4, accessing a path containing . did not fallback to index.html even if appType is set to 'SPA' (default). From Vite 5, it will fallback to index.html.

Note that the browser will no longer show the 404 error message in the console if you point the image path to a non-existent file (e.g. <img src="./file-does-not-exist.png">).

Manifest files are now generated in .vite directory by default

In Vite 4, the manifest files (build.manifest, build.ssrManifest) was generated in the root of build.outDir by default. From Vite 5, those will be generated in the .vite directory in the build.outDir by default.

CLI shortcuts require an additional Enter press

CLI shortcuts, like r to restart the dev server, now require an additional Enter press to trigger the shortcut. For example, r + Enter to restart the dev server.

This change prevents Vite from swallowing and controlling OS-specific shortcuts, allowing better compatibility when combining the Vite dev server with other processes, and avoids the previous caveats.

Remove --https flag and https: true

--https flag sets https: true. This config was meant to be used together with the automatic https certification generation feature which was dropped in Vite 3. This config no longer makes sense as it will make Vite start a HTTPS server without a certificate. Both @vitejs/plugin-basic-ssl and vite-plugin-mkcert sets https setting regardless of the https value, so you can just remove --https and https: true.

Remove resolvePackageEntry and resolvePackageData APIs

The resolvePackageEntry and resolvePackageData APIs are removed as they exposed Vite's internals and blocked potential Vite 4.3 optimizations in the past. These APIs can be replaced with third-party packages, for example:

import { resolve } from 'import-meta-env'
import { findDepPkgJsonPath } from 'vitefu'
import fs from 'node:fs'

const pkg = 'my-lib'
const basedir = process.cwd()

// `resolvePackageEntry`:
const packageEntry = resolve(pkg, basedir)

// `resolvePackageData`:
const packageJsonPath = findDepPkgJsonPath(pkg, basedir)
const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, 'utf-8'))

Removed Deprecated APIs

  • Default exports of CSS files (e.g import style from './foo.css'): Use the ?inline query instead
  • import.meta.globEager: Use import.meta.glob('*', { eager: true }) instead
  • ssr.format: 'cjs' and legacy.buildSsrCjsExternalHeuristics (#13816)
  • server.middlewareMode: 'ssr' and server.middlewareMode: 'html': Use appType + server.middlewareMode: true instead (#8452)

Advanced

There are some changes which only affect plugin/tool creators.

Also there are other breaking changes which only affect few users.

Migration from v3

Check the Migration from v3 Guide in the Vite v4 docs first to see the needed changes to port your app to Vite v4, and then proceed with the changes on this page.