"vite" rewrites "named import" of typescript enums as "default import" and breaks app

[superboum]

Describe the bug

I try to use a named import (import { Status } from 'ts-enum/status.ts'), I expect the import to work (it works with yarn build), but vite rewrites it as a "default import" (cf below) which is wrong (cf error).

vite import rewrite:

import __vite__cjsImport0_tsEnum_status from "/node_modules/.vite/deps/ts-enum_status.js?v=af7bba1f"; const Status = __vite__cjsImport0_tsEnum_status["Status"];

browser error (from dev console, both Firefox and Chrome):

main.ts:1 Uncaught SyntaxError: The requested module '/node_modules/.vite/deps/ts-enum_status.js?v=d7be5188' does not provide an export named 'default' (at main.ts:1:1)

Issues that might be related: #17727 ; #11231 ; #14018 ; #11783 ; #15434 ; #17619 ; #16742 ; #16293 ; #15620

Reproduction

https://gist.github.com/superboum/1d59a67290a3224d83fbc5cb7f97fb03

Steps to reproduce

Create a simple typescript module:

mkdir ts-enum
cd ts-enum
yarn init --yes
echo "export enum Status { GREEN = 'GREEN' }" > status.ts
# :warning: The issue seems directly related to enums. If we replace the enum by a struct, the error does not occur:
# echo 'export let Status = { "GREEN": "GREEN" }' > status.ts
cd ..

Create a vite project with the typescript template:

yarn create vite vite-bug --template vanilla-ts
cd vite-bug

Replace yarn PnP module resolution with the traditional node-modules

yarn config set nodeLinker node-modules

Now add our dependency (problem also exists if the dependency is pulled from git or a npm registry):

yarn add ts-enum@file:./../ts-enum
yarn install

Write the most straightforward javascript that will trigger the bug:

echo "import { Status } from 'ts-enum/status'" > src/main.ts
echo 'console.log(Status.GREEN)' >> src/main.ts

Building works perfectly, you can try with:

yarn build
cd dist ; python -m http.server
# go to http://localhost:8000 ; open the dev console ; see no error, only a `GREEN` console log. It works!

But vite breaks our app:

yarn dev
# go to http://localhost:5173 ; open the dev console ; see an import error

System Info

  System:
    OS: Linux 6.6 NixOS 24.05 (Uakari) 24.05 (Uakari)
    CPU: (4) x64 Intel(R) Core(TM) i7-4500U CPU @ 1.80GHz
    Memory: 9.71 GB / 15.53 GB
    Container: Yes
    Shell: 5.2.26 - /nix/store/pg0zqlym7y3cd8631b3x6cghxcmjl8xa-bash-interactive-5.2p26/bin/bash
  Binaries:
    Node: 18.20.4 - /run/current-system/sw/bin/node
    Yarn: 4.2.2 - /nix/store/wvalqmxg0275mf7alwyl0x0fvjbgcb8j-yarn-berry-4.2.2/bin/yarn
    npm: 10.7.0 - /run/current-system/sw/bin/npm
  Browsers:
    Chromium: 127.0.6533.88
    Firefox: 129.0
  npmPackages:
    vite: ^5.4.0 => 5.4.0

Used Package Manager

yarn

Logs

vite and vite build do not produce any error.
But loading the website in a browser with vite will produce this error:

main.ts:1 Uncaught SyntaxError: The requested module '/node_modules/.vite/deps/ts-enum_status.js?v=d7be5188' does not provide an export named 'default' (at main.ts:1:1)

Still, the output of vite --debug:

Reveal output

[nix-shell:/tmp/vite-bug]$ yarn run vite --debug
  vite:config no config file found. +0ms
  vite:config using resolved config: {
  vite:config   root: '/tmp/vite-bug',
  vite:config   base: '/',
  vite:config   mode: 'development',
  vite:config   configFile: undefined,
  vite:config   logLevel: undefined,
  vite:config   clearScreen: undefined,
  vite:config   optimizeDeps: {
  vite:config     holdUntilCrawlEnd: true,
  vite:config     force: undefined,
  vite:config     esbuildOptions: { preserveSymlinks: false }
  vite:config   },
  vite:config   server: {
  vite:config     preTransformRequests: true,
  vite:config     host: undefined,
  vite:config     sourcemapIgnoreList: [Function: isInNodeModules$1],
  vite:config     middlewareMode: false,
  vite:config     fs: {
  vite:config       strict: true,
  vite:config       allow: [Array],
  vite:config       deny: [Array],
  vite:config       cachedChecks: undefined
  vite:config     }
  vite:config   },
  vite:config   configFileDependencies: [],
  vite:config   inlineConfig: {
  vite:config     root: undefined,
  vite:config     base: undefined,
  vite:config     mode: undefined,
  vite:config     configFile: undefined,
  vite:config     logLevel: undefined,
  vite:config     clearScreen: undefined,
  vite:config     optimizeDeps: { force: undefined },
  vite:config     server: { host: undefined }
  vite:config   },
  vite:config   decodedBase: '/',
  vite:config   rawBase: '/',
  vite:config   resolve: {
  vite:config     mainFields: [ 'browser', 'module', 'jsnext:main', 'jsnext' ],
  vite:config     conditions: [],
  vite:config     extensions: [
  vite:config       '.mjs',  '.js',
  vite:config       '.mts',  '.ts',
  vite:config       '.jsx',  '.tsx',
  vite:config       '.json'
  vite:config     ],
  vite:config     dedupe: [],
  vite:config     preserveSymlinks: false,
  vite:config     alias: [ [Object], [Object] ]
  vite:config   },
  vite:config   publicDir: '/tmp/vite-bug/public',
  vite:config   cacheDir: '/tmp/vite-bug/node_modules/.vite',
  vite:config   command: 'serve',
  vite:config   ssr: {
  vite:config     target: 'node',
  vite:config     optimizeDeps: { noDiscovery: true, esbuildOptions: [Object] }
  vite:config   },
  vite:config   isWorker: false,
  vite:config   mainConfig: null,
  vite:config   bundleChain: [],
  vite:config   isProduction: false,
  vite:config   plugins: [
  vite:config     'vite:optimized-deps',
  vite:config     'vite:watch-package-data',
  vite:config     'vite:pre-alias',
  vite:config     'alias',
  vite:config     'vite:modulepreload-polyfill',
  vite:config     'vite:resolve',
  vite:config     'vite:html-inline-proxy',
  vite:config     'vite:css',
  vite:config     'vite:esbuild',
  vite:config     'vite:json',
  vite:config     'vite:wasm-helper',
  vite:config     'vite:worker',
  vite:config     'vite:asset',
  vite:config     'vite:wasm-fallback',
  vite:config     'vite:define',
  vite:config     'vite:css-post',
  vite:config     'vite:worker-import-meta-url',
  vite:config     'vite:asset-import-meta-url',
  vite:config     'vite:dynamic-import-vars',
  vite:config     'vite:import-glob',
  vite:config     'vite:client-inject',
  vite:config     'vite:css-analysis',
  vite:config     'vite:import-analysis'
  vite:config   ],
  vite:config   css: { lightningcss: undefined },
  vite:config   esbuild: { jsxDev: true },
  vite:config   build: {
  vite:config     target: [ 'es2020', 'edge88', 'firefox78', 'chrome87', 'safari14' ],
  vite:config     cssTarget: [ 'es2020', 'edge88', 'firefox78', 'chrome87', 'safari14' ],
  vite:config     outDir: 'dist',
  vite:config     assetsDir: 'assets',
  vite:config     assetsInlineLimit: 4096,
  vite:config     cssCodeSplit: true,
  vite:config     sourcemap: false,
  vite:config     rollupOptions: {},
  vite:config     minify: 'esbuild',
  vite:config     terserOptions: {},
  vite:config     write: true,
  vite:config     emptyOutDir: null,
  vite:config     copyPublicDir: true,
  vite:config     manifest: false,
  vite:config     lib: false,
  vite:config     ssr: false,
  vite:config     ssrManifest: false,
  vite:config     ssrEmitAssets: false,
  vite:config     reportCompressedSize: true,
  vite:config     chunkSizeWarningLimit: 500,
  vite:config     watch: null,
  vite:config     commonjsOptions: { include: [Array], extensions: [Array] },
  vite:config     dynamicImportVarsOptions: { warnOnError: true, exclude: [Array] },
  vite:config     modulePreload: { polyfill: true },
  vite:config     cssMinify: true
  vite:config   },
  vite:config   preview: {
  vite:config     port: undefined,
  vite:config     strictPort: undefined,
  vite:config     host: undefined,
  vite:config     https: undefined,
  vite:config     open: undefined,
  vite:config     proxy: undefined,
  vite:config     cors: undefined,
  vite:config     headers: undefined
  vite:config   },
  vite:config   envDir: '/tmp/vite-bug',
  vite:config   env: { BASE_URL: '/', MODE: 'development', DEV: true, PROD: false },
  vite:config   assetsInclude: [Function: assetsInclude],
  vite:config   logger: {
  vite:config     hasWarned: false,
  vite:config     info: [Function: info],
  vite:config     warn: [Function: warn],
  vite:config     warnOnce: [Function: warnOnce],
  vite:config     error: [Function: error],
  vite:config     clearScreen: [Function: clearScreen],
  vite:config     hasErrorLogged: [Function: hasErrorLogged]
  vite:config   },
  vite:config   packageCache: Map(1) {
  vite:config     'fnpd_/tmp/vite-bug' => {
  vite:config       dir: '/tmp/vite-bug',
  vite:config       data: [Object],
  vite:config       hasSideEffects: [Function: hasSideEffects],
  vite:config       webResolvedImports: {},
  vite:config       nodeResolvedImports: {},
  vite:config       setResolvedCache: [Function: setResolvedCache],
  vite:config       getResolvedCache: [Function: getResolvedCache]
  vite:config     },
  vite:config     set: [Function (anonymous)]
  vite:config   },
  vite:config   createResolver: [Function: createResolver],
  vite:config   worker: { format: 'iife', plugins: '() => plugins', rollupOptions: {} },
  vite:config   appType: 'spa',
  vite:config   experimental: { importGlobRestoreExtension: false, hmrPartialAccept: false },
  vite:config   getSortedPlugins: [Function: getSortedPlugins],
  vite:config   getSortedPluginHooks: [Function: getSortedPluginHooks]
  vite:config } +10ms
  vite:deps Hash is consistent. Skipping. Use --force to override. +0ms

  VITE v5.4.0  ready in 194 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help
  vite:html-fallback Rewriting GET / to /index.html +0ms
  vite:time 38.75ms /index.html +0ms
  vite:resolve 7.77ms /src/main.ts -> /tmp/vite-bug/src/main.ts +0ms
  vite:load 22.27ms [fs] /src/main.ts +0ms
  vite:resolve 0.56ms ts-enum/status -> /tmp/vite-bug/node_modules/.vite/deps/ts-enum_status.js?v=30357745 +75ms
  vite:import-analysis /node_modules/.vite/deps/ts-enum_status.js?v=30357745 needs interop +0ms
  vite:optimize-deps load /tmp/vite-bug/node_modules/.vite/deps/ts-enum_status.js +0ms
  vite:import-analysis 8.90ms [1 imports rewritten] src/main.ts +5ms
  vite:transform 55.90ms /src/main.ts +0ms
  vite:load 6.74ms [plugin] /node_modules/.vite/deps/ts-enum_status.js?v=30357745 +64ms
  vite:import-analysis 0.48ms [no imports] node_modules/.vite/deps/ts-enum_status.js?v=30357745 +7ms
  vite:transform 1.35ms /node_modules/.vite/deps/ts-enum_status.js?v=30357745 +7ms
  vite:resolve 0.98ms /@vite/client -> /tmp/vite-bug/node_modules/vite/dist/client/client.mjs +128ms
  vite:cache [memory] /src/main.ts +0ms
  vite:time 1.83ms /src/main.ts +215ms
  vite:load 6.60ms [fs] /@vite/client +125ms
  vite:resolve 0.45ms @vite/env -> /tmp/vite-bug/node_modules/vite/dist/client/env.mjs +15ms
  vite:import-analysis 7.85ms [1 imports rewritten] node_modules/vite/dist/client/client.mjs +133ms
  vite:transform 8.80ms /@vite/client +133ms
  vite:time 19.86ms /@vite/client +12ms
  vite:load 5.62ms [fs] /node_modules/vite/dist/client/env.mjs +15ms
  vite:import-analysis 0.10ms [no imports] node_modules/vite/dist/client/env.mjs +6ms
  vite:transform 0.49ms /node_modules/vite/dist/client/env.mjs +6ms
  vite:cache [memory] /node_modules/.vite/deps/ts-enum_status.js?v=30357745 +36ms
  vite:time 0.60ms /node_modules/.vite/deps/ts-enum_status.js?v=30357745 +23ms
  vite:cache [304] /node_modules/vite/dist/client/env.mjs +0ms
  vite:time 0.31ms /node_modules/vite/dist/client/env.mjs +60ms

Workaround

Excluding ts-enum (the dependency containing an enum) from optimization seems to fix the issue.
It worked for me with the following vite.config.js on the reproduction project:

import { defineConfig } from 'vite'

export default defineConfig({
    optimizeDeps: {
        exclude: [
	  'ts-enum',
	],
    },
})

And then the import is not broken anymore:

import { Status } from "/node_modules/ts-enum/status.ts?v=23ac7d0a";

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[hi-ogawa]

The issues you linked don't look relevant. Probably this is due to a false detection of cjs in optimizer and a similar issue I remember is this one:

• Empty modules in optimized dependencies compile incorrectly #16315
• fix: adjust esm syntax judgment logic #16436

---

After some digging, it looks like es-module-lexer somehow manages to "succeed" parsing the ts file, but it's returning hasModuleSyntax: false. If it were failing, then it'll probably get parsed properly as typescript and esm, but it didn't get that chance.

vite/packages/vite/src/node/optimizer/index.ts

Lines 1092 to 1105 in 6700594

	const entryContent = await fsp.readFile(filePath, 'utf-8')
	try {
	parseResult = parse(entryContent)
	} catch {
	const loader = esbuildOptions.loader?.[path.extname(filePath)] || 'jsx'
	debug?.(
	`Unable to parse: ${filePath}.\n Trying again with a ${loader} transform.`,
	)
	const transformed = await transformWithEsbuild(entryContent, filePath, {
	loader,
	})
	parseResult = parse(transformed.code)
	usedJsxLoader = true
	}

I made a simpler reproduction here

• https://github.com/hi-ogawa/reproductions/tree/main/vite-17878-ts-enum-export-optimizer
• https://stackblitz.com/github/hi-ogawa/reproductions/tree/main/vite-17878-ts-enum-export-optimizer

[sapphi-red]

es-module-lexer requires the input to be a valid JS, so probably we should check the file extension before running parse.