`createServerFn` @tanstack/start-server-core leaking into client bundle

[ian-pascoe]

Which project does this relate to?

Start

Describe the bug

When using createServerFn some of the server code is leaking into the client bundle as shown in the warning messages and error below:

❯ pnpm run build
\
> @theaistudybible/www@ build /Users/ianpascoe/Code/theaistudybible/apps/www
> vinxi build

vinxi v0.5.4


⚙  Building your app...
vinxi v0.5.4


⚙ Building your router client...


📦 Compiling client router...
vinxi building router client in client mode

♻️  Generating routes...
✅ Processed routes in 139ms
vite v6.2.6 building for production...
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-client-core@1.115.3/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:path" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-client-core@1.115.3/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-client-core@1.115.3/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:path" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-client-core@1.115.3/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:stream" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+react-start-server@1.116.0_react-dom@19.1.0_react@19.1.0__react@19.1.0/node_modules/@tanstack/react-start-server/dist/esm/defaultStreamHandler.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:stream/web" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:stream" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:async_hooks" has been externalized for browser compatibility, imported by "/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/h3.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
✓ 3051 modules transformed.

PWA v1.0.0
Building app/service-worker.ts service worker ("es" format)...
vite v6.2.6 building for production...
✓ 70 modules transformed.
.vinxi/build/client/_build/service-worker.mjs  17.12 kB │ gzip: 5.78 kB
✓ built in 101ms

PWA v1.0.0
mode      injectManifest
format:   es
precache  2 entries (0.00 KiB)
files generated
  .vinxi/build/client/_build/service-worker.js
warnings
  One of the glob patterns doesn't match any files. Please remove or fix the following: {
  "globDirectory": "/Users/ianpascoe/Code/theaistudybible/apps/www/.vinxi/build/client/_build",
  "globPattern": "**/*.{js,css,html,png,svg,ico,wasm,webp,woff,woff2,ttf,eot,json,jpg,jpeg,gif,mp3,mp4,wav,avif}",
  "globIgnores": [
    "**/node_modules/**/*",
    "service-worker.js",
    "service-worker.js"
  ]
}

✗ Build failed in 6.79s

 ERROR  [vite-plugin-pwa:build] There was an error during the build:                                                        11:32:32 AM
  ../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js (2:9): "Readable" is not exported by "__vite-browser-external", imported by "../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js".
Additionally, handling the error in the 'buildEnd' hook caused the following error:
  ../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js (2:9): "Readable" is not exported by "__vite-browser-external", imported by "../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js".
file: /Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js:2:9

1: import { ReadableStream } from "node:stream/web";
2: import { Readable } from "node:stream";
            ^
3: import { createControlledPromise } from "@tanstack/router-core";
4: function transformReadableStreamWithRouter(router, routerStream) {


    at getRollupError (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/rollup@4.40.0/node_modules/rollup/dist/es/shared/parseAst.js:397:41)
    at /Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/rollup@4.40.0/node_modules/rollup/dist/es/shared/node-entry.js:23076:39
    at async catchUnfinishedHookActions (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/rollup@4.40.0/node_modules/rollup/dist/es/shared/node-entry.js:22540:16)
    at async rollupInternal (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/rollup@4.40.0/node_modules/rollup/dist/es/shared/node-entry.js:23059:5)
    at async buildEnvironment (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/vite@6.2.6_@types+node@22.14.1_jiti@2.4.2_lightningcss@1.29.2_terser@5.39.0_tsx@4.19.3_yaml@2.7.1/node_modules/vite/dist/node/chunks/dep-Bid9ssRr.js:51506:14)
    at async createViteBuild (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/vinxi@0.5.4_@libsql+client@0.15.3_@types+node@22.14.1_@upstash+redis@1.34.7_db0@0.3.1_@_d95f9dbdce65deaf792ada549192fef2/node_modules/vinxi/lib/build.js:395:17)
    at async createRouterBuild (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/vinxi@0.5.4_@libsql+client@0.15.3_@types+node@22.14.1_@upstash+redis@1.34.7_db0@0.3.1_@_d95f9dbdce65deaf792ada549192fef2/node_modules/vinxi/lib/build.js:529:2)
    at async /Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/vinxi@0.5.4_@libsql+client@0.15.3_@types+node@22.14.1_@upstash+redis@1.34.7_db0@0.3.1_@_d95f9dbdce65deaf792ada549192fef2/node_modules/vinxi/lib/build.js:59:5
    at async createBuild (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/vinxi@0.5.4_@libsql+client@0.15.3_@types+node@22.14.1_@upstash+redis@1.34.7_db0@0.3.1_@_d95f9dbdce65deaf792ada549192fef2/node_modules/vinxi/lib/build.js:58:4)
    at async Object.run (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/vinxi@0.5.4_@libsql+client@0.15.3_@types+node@22.14.1_@upstash+redis@1.34.7_db0@0.3.1_@_d95f9dbdce65deaf792ada549192fef2/node_modules/vinxi/bin/cli.mjs:235:5)
    at async runCommand (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/citty@0.1.6/node_modules/citty/dist/index.mjs:316:16)
    at async runCommand (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/citty@0.1.6/node_modules/citty/dist/index.mjs:307:11)
    at async runMain (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/citty@0.1.6/node_modules/citty/dist/index.mjs:445:7) 



 ERROR  [vite-plugin-pwa:build] There was an error during the build:                                                        11:32:32 AM
  ../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js (2:9): "Readable" is not exported by "__vite-browser-external", imported by "../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js".
Additionally, handling the error in the 'buildEnd' hook caused the following error:
  ../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js (2:9): "Readable" is not exported by "__vite-browser-external", imported by "../../node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js".
file: /Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/@tanstack+start-server-core@1.115.3/node_modules/@tanstack/start-server-core/dist/esm/transformStreamWithRouter.js:2:9

1: import { ReadableStream } from "node:stream/web";
2: import { Readable } from "node:stream";
            ^
3: import { createControlledPromise } from "@tanstack/router-core";
4: function transformReadableStreamWithRouter(router, routerStream) {



 ERROR  Exited with code: 1                                                                                                 11:32:32 AM

    at CommandChild.pipedStdoutBuffer (/Users/ianpascoe/Code/theaistudybible/node_modules/.pnpm/dax-sh@0.39.2/node_modules/dax-sh/esm/mod.js:9392:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) 



 ERROR  Exited with code: 1 

Your Example Website or App

https://github.com/spirit-led-software/theaistudybible

Steps to Reproduce the Bug or Issue

1. Run pnpm build from within apps/www
2. Observer the failure

Expected behavior

As a user, I expected my production build to build successfully and not have server/client bundle issues

Screenshots or Videos

No response

Platform

• OS: macOS
• Browser: Vivaldi
• Version: 7

Additional context

No response

[letstri]

I had the same problem, I think you are trying to use some server function like getHeader on the client.

[tswymer]

I'm running into the same issue, can reproduce using the start-basic example:

1. npx gitpick TanStack/router/tree/main/examples/react/start-basic start-basic
2. cd start-basic
3. npm install
4. npm build

start-basic % npm run build

> build
> vinxi build

vinxi v0.5.3


⚙  Building your app...
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/client
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/ssr
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/server
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/api
vinxi v0.5.3


⚙ Building your router client...


📦 Compiling client router...
vinxi building router client in client mode

♻️  Generating routes...
✅ Processed routes in 156ms
vite v6.3.4 building for production...
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:path" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:path" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
virtual:$vinxi/handler/client (1:106): "default" is not exported by "src/client.tsx", imported by "virtual:$vinxi/handler/client".
✓ 189 modules transformed.
.vinxi/build/client/_build/.vite/manifest.json                           7.47 kB │ gzip:  0.95 kB
.vinxi/build/client/_build/assets/app-DU2gGyHe.css                       7.30 kB │ gzip:  2.09 kB
.vinxi/build/client/_build/assets/__vite-browser-external-BIHI7g3E.js    0.03 kB │ gzip:  0.05 kB
.vinxi/build/client/_build/assets/client-CLK42Prl.js                     0.06 kB │ gzip:  0.08 kB
.vinxi/build/client/_build/assets/posts._postId-DNaHGGLA.js              0.11 kB │ gzip:  0.12 kB
.vinxi/build/client/_build/assets/posts_._postId.deep-E5joyy4z.js        0.11 kB │ gzip:  0.12 kB
.vinxi/build/client/_build/assets/PostError-CDtlP0eQ.js                  0.11 kB │ gzip:  0.12 kB
.vinxi/build/client/_build/assets/route-b-CSpC05IQ.js                    0.13 kB │ gzip:  0.13 kB
.vinxi/build/client/_build/assets/route-a-DBPMMR1Z.js                    0.13 kB │ gzip:  0.13 kB
.vinxi/build/client/_build/assets/users._userId-CM751gHQ.js              0.13 kB │ gzip:  0.14 kB
.vinxi/build/client/_build/assets/posts._postId-TbZnoE70.js              0.13 kB │ gzip:  0.13 kB
.vinxi/build/client/_build/assets/users.index-C88qWrm3.js                0.13 kB │ gzip:  0.14 kB
.vinxi/build/client/_build/assets/posts.index-DjZIXhUy.js                0.13 kB │ gzip:  0.14 kB
.vinxi/build/client/_build/assets/users._userId-DzT_OH2F.js              0.14 kB │ gzip:  0.13 kB
.vinxi/build/client/_build/assets/index-DzBMORpB.js                      0.17 kB │ gzip:  0.16 kB
.vinxi/build/client/_build/assets/_pathlessLayout-HuTKlhpS.js            0.24 kB │ gzip:  0.19 kB
.vinxi/build/client/_build/assets/users._userId-DkLITMWk.js              0.30 kB │ gzip:  0.22 kB
.vinxi/build/client/_build/assets/posts_._postId.deep-CAEATBr3.js        0.41 kB │ gzip:  0.29 kB
.vinxi/build/client/_build/assets/_nested-layout-BkTaFxnb.js             0.45 kB │ gzip:  0.26 kB
.vinxi/build/client/_build/assets/posts._postId-Cj79Vi-Q.js              0.49 kB │ gzip:  0.32 kB
.vinxi/build/client/_build/assets/users.route-B7WNoi_E.js                0.60 kB │ gzip:  0.39 kB
.vinxi/build/client/_build/assets/posts.route-CilHwWe-.js                0.60 kB │ gzip:  0.39 kB
.vinxi/build/client/_build/assets/deferred-DKLB-S2l.js                   0.82 kB │ gzip:  0.40 kB
.vinxi/build/client/_build/assets/client-B8y9h1oh.js                   278.76 kB │ gzip: 89.29 kB
✓ built in 905ms
✔ build done                                                                                                                                            1:13:19 PM
⚙ Built your router client successfully
vinxi v0.5.3


⚙ Building your router ssr...


📦 Compiling ssr router...
vinxi building router ssr in http mode
vite v6.3.4 building SSR bundle for production...
"clientOnly", "createIsomorphicFn", "globalMiddleware", "json" and "serverOnly" are imported from external module "@tanstack/start-client-core" but never used in "node_modules/@tanstack/react-start-client/dist/esm/StartClient.js", "node_modules/@tanstack/react-start-client/dist/esm/index.js", "node_modules/@tanstack/start-server-functions-fetcher/dist/esm/index.js" and "node_modules/@tanstack/start-server-functions-ssr/dist/esm/index.js".
✓ 67 modules transformed.
.vinxi/build/ssr/.vite/manifest.json                      6.55 kB
.vinxi/build/ssr/assets/app-DU2gGyHe.css                  7.30 kB
.vinxi/build/ssr/assets/route-b-D9PRTkM1.js               0.12 kB
.vinxi/build/ssr/assets/route-a-E7oJVDbm.js               0.12 kB
.vinxi/build/ssr/assets/users.index-C_G0zRko.js           0.13 kB
.vinxi/build/ssr/assets/posts.index-GrcD0GTd.js           0.13 kB
.vinxi/build/ssr/assets/posts._postId-CCFyNDhO.js         0.14 kB
.vinxi/build/ssr/assets/posts_._postId.deep-CCFyNDhO.js   0.14 kB
.vinxi/build/ssr/assets/PostError-DXPFgQzs.js             0.16 kB
.vinxi/build/ssr/assets/index-CuMTP0jl.js                 0.16 kB
.vinxi/build/ssr/assets/users._userId-CxO9mclU.js         0.18 kB
.vinxi/build/ssr/assets/_pathlessLayout-BhUDWYaS.js       0.27 kB
.vinxi/build/ssr/ssr.js                                   0.35 kB
.vinxi/build/ssr/assets/users._userId-C44Gwmbi.js         0.41 kB
.vinxi/build/ssr/assets/posts._postId-DMFJUzkr.js         0.41 kB
.vinxi/build/ssr/assets/_nested-layout-BHe2HPJb.js        0.47 kB
.vinxi/build/ssr/assets/users._userId-aLGGtNIx.js         0.58 kB
.vinxi/build/ssr/assets/posts_._postId.deep-BlGBrBVX.js   0.70 kB
.vinxi/build/ssr/assets/posts._postId-CpcxQml2.js         0.77 kB
.vinxi/build/ssr/assets/users.route-Di_yysHc.js           0.88 kB
.vinxi/build/ssr/assets/posts.route-Dgd06a6V.js           0.88 kB
.vinxi/build/ssr/assets/deferred-DNLgJPzn.js              1.08 kB
.vinxi/build/ssr/assets/ssr-CKliUiKE.js                  14.09 kB
✓ built in 410ms
✔ build done                                                                                                                                            1:13:20 PM
⚙ Built your router ssr successfully
vinxi v0.5.3


⚙ Building your router server...


📦 Compiling server router...
vinxi building router server in http mode
vite v6.3.4 building SSR bundle for production...
"clientOnly", "createIsomorphicFn", "globalMiddleware", "json", "mergeHeaders" and "serverOnly" are imported from external module "@tanstack/start-client-core" but never used in "node_modules/@tanstack/react-start-client/dist/esm/StartClient.js", "node_modules/@tanstack/react-start-client/dist/esm/index.js" and "node_modules/@tanstack/start-server-functions-handler/dist/esm/index.js".
✓ 18 modules transformed.
.vinxi/build/server/_server/.vite/manifest.json          1.37 kB
.vinxi/build/server/_server/assets/index-ujMS-7Qz.js     0.28 kB
.vinxi/build/server/_server/assets/posts-BA7Lzkzg.js     0.96 kB
.vinxi/build/server/_server/assets/deferred-B8VZvB08.js  1.06 kB
.vinxi/build/server/_server/assets/deferred-CUk1YZ6L.js  1.85 kB
.vinxi/build/server/_server/server.js                    3.82 kB
✓ built in 223ms
✔ build done                                                                                                                                            1:13:21 PM
⚙ Built your router server successfully
vinxi v0.5.3


⚙ Building your router api...


📦 Compiling api router...
vinxi building router api in http mode
vite v6.3.4 building SSR bundle for production...
"clientOnly", "createIsomorphicFn", "createMiddleware", "createServerFn", "globalMiddleware", "mergeHeaders", "registerGlobalMiddleware", "serverOnly" and "startSerializer" are imported from external module "@tanstack/start-client-core" but never used in "node_modules/@tanstack/react-start-client/dist/esm/StartClient.js" and "node_modules/@tanstack/react-start-client/dist/esm/index.js".
✓ 14 modules transformed.
.vinxi/build/api/api/.vite/manifest.json       1.02 kB
.vinxi/build/api/api/api.js                    0.13 kB
.vinxi/build/api/api/users.js                  0.46 kB
.vinxi/build/api/api/users._id.js              0.55 kB
.vinxi/build/api/api/assets/index-C_-U9-id.js  4.05 kB
✓ built in 171ms
✔ build done                                                                                                                                            1:13:22 PM
⚙ Built your router api successfully


⚙  Preparing app for node-server...
✔ Generated public .output/public                                                                                                                 vinxi 1:13:22 PM
ℹ Building Nitro Server (preset: node-server, compatibility date: 2024-12-01)                                                                     vinxi 1:13:22 PM
✔ Nitro Server built                                                                                                                              vinxi 1:13:23 PM
✔ You can preview this build using node .output/server/index.mjs                                                                                  vinxi 1:13:23 PM```

[K-Mistele]

+1, same issue here.

[ian-pascoe]

I had the same problem, I think you are trying to use some server function like getHeader on the client.

This solved it for me. I was using getCookie in the client. Tried to section it into a block where typeof window === "undefined", but it didn't split the code out.

[cherishh]

I'm running into the same issue, can reproduce using the start-basic example:

1. npx gitpick TanStack/router/tree/main/examples/react/start-basic start-basic
2. cd start-basic
3. npm install
4. npm build

start-basic % npm run build

> build
> vinxi build

vinxi v0.5.3


⚙  Building your app...
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/client
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/ssr
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/server
removing /Users/tobias/Documents/Development/start-basic/.vinxi/build/api
vinxi v0.5.3


⚙ Building your router client...


📦 Compiling client router...
vinxi building router client in client mode

♻️  Generating routes...
✅ Processed routes in 156ms
vite v6.3.4 building for production...
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:path" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:path" has been externalized for browser compatibility, imported by "/Users/tobias/Documents/Development/start-basic/node_modules/@tanstack/start-client-core/dist/esm/createServerFn.js". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
virtual:$vinxi/handler/client (1:106): "default" is not exported by "src/client.tsx", imported by "virtual:$vinxi/handler/client".
✓ 189 modules transformed.
.vinxi/build/client/_build/.vite/manifest.json                           7.47 kB │ gzip:  0.95 kB
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.vinxi/build/client/_build/assets/__vite-browser-external-BIHI7g3E.js    0.03 kB │ gzip:  0.05 kB
.vinxi/build/client/_build/assets/client-CLK42Prl.js                     0.06 kB │ gzip:  0.08 kB
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✓ built in 905ms
✔ build done                                                                                                                                            1:13:19 PM
⚙ Built your router client successfully
vinxi v0.5.3


⚙ Building your router ssr...


📦 Compiling ssr router...
vinxi building router ssr in http mode
vite v6.3.4 building SSR bundle for production...
"clientOnly", "createIsomorphicFn", "globalMiddleware", "json" and "serverOnly" are imported from external module "@tanstack/start-client-core" but never used in "node_modules/@tanstack/react-start-client/dist/esm/StartClient.js", "node_modules/@tanstack/react-start-client/dist/esm/index.js", "node_modules/@tanstack/start-server-functions-fetcher/dist/esm/index.js" and "node_modules/@tanstack/start-server-functions-ssr/dist/esm/index.js".
✓ 67 modules transformed.
.vinxi/build/ssr/.vite/manifest.json                      6.55 kB
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.vinxi/build/ssr/assets/posts.route-Dgd06a6V.js           0.88 kB
.vinxi/build/ssr/assets/deferred-DNLgJPzn.js              1.08 kB
.vinxi/build/ssr/assets/ssr-CKliUiKE.js                  14.09 kB
✓ built in 410ms
✔ build done                                                                                                                                            1:13:20 PM
⚙ Built your router ssr successfully
vinxi v0.5.3


⚙ Building your router server...


📦 Compiling server router...
vinxi building router server in http mode
vite v6.3.4 building SSR bundle for production...
"clientOnly", "createIsomorphicFn", "globalMiddleware", "json", "mergeHeaders" and "serverOnly" are imported from external module "@tanstack/start-client-core" but never used in "node_modules/@tanstack/react-start-client/dist/esm/StartClient.js", "node_modules/@tanstack/react-start-client/dist/esm/index.js" and "node_modules/@tanstack/start-server-functions-handler/dist/esm/index.js".
✓ 18 modules transformed.
.vinxi/build/server/_server/.vite/manifest.json          1.37 kB
.vinxi/build/server/_server/assets/index-ujMS-7Qz.js     0.28 kB
.vinxi/build/server/_server/assets/posts-BA7Lzkzg.js     0.96 kB
.vinxi/build/server/_server/assets/deferred-B8VZvB08.js  1.06 kB
.vinxi/build/server/_server/assets/deferred-CUk1YZ6L.js  1.85 kB
.vinxi/build/server/_server/server.js                    3.82 kB
✓ built in 223ms
✔ build done                                                                                                                                            1:13:21 PM
⚙ Built your router server successfully
vinxi v0.5.3


⚙ Building your router api...


📦 Compiling api router...
vinxi building router api in http mode
vite v6.3.4 building SSR bundle for production...
"clientOnly", "createIsomorphicFn", "createMiddleware", "createServerFn", "globalMiddleware", "mergeHeaders", "registerGlobalMiddleware", "serverOnly" and "startSerializer" are imported from external module "@tanstack/start-client-core" but never used in "node_modules/@tanstack/react-start-client/dist/esm/StartClient.js" and "node_modules/@tanstack/react-start-client/dist/esm/index.js".
✓ 14 modules transformed.
.vinxi/build/api/api/.vite/manifest.json       1.02 kB
.vinxi/build/api/api/api.js                    0.13 kB
.vinxi/build/api/api/users.js                  0.46 kB
.vinxi/build/api/api/users._id.js              0.55 kB
.vinxi/build/api/api/assets/index-C_-U9-id.js  4.05 kB
✓ built in 171ms
✔ build done                                                                                                                                            1:13:22 PM
⚙ Built your router api successfully


⚙  Preparing app for node-server...
✔ Generated public .output/public                                                                                                                 vinxi 1:13:22 PM
ℹ Building Nitro Server (preset: node-server, compatibility date: 2024-12-01)                                                                     vinxi 1:13:22 PM
✔ Nitro Server built                                                                                                                              vinxi 1:13:23 PM
✔ You can preview this build using node .output/server/index.mjs                                                                                  vinxi 1:13:23 PM```

sorry for my stupidity, where does it leaked?

[martin-dimi]

Having the same issue.

[lewsmith]

Same issue here with a fresh install following the start-basic guide

[eblanchette]

I experienced something similar when using setCookie. Manage to resolve it by wrapping the function in a serverOnly function. Hope this helps

export const setTokens = serverOnly(async (access: string, refresh: string) => {
  setCookie("access_token", access, {
    httpOnly: true,
    sameSite: "lax",
    path: "/",
    maxAge: 34560000,
  });
  setCookie("refresh_token", refresh, {
    httpOnly: true,
    sameSite: "lax",
    path: "/",
    maxAge: 34560000,
  });
});

[xuxucode]

To avoid importing server modules in client side, try to create the src/server.ts server entry file (v1.121.1+), and import them there, see #2783 (comment)

[Nedi11]

same issue code in createserverfn leaking into client

[ilkergzlkkr]

Creating a separate file for only server function and default exporting it works for me

[brenelz]

Is this still an issue in the latest version of start? It no longer uses vinxi

[GodGardensGuns]

This was still an issue for me using Vite. Using import.meta.env.SSR instead of typeof window == 'undefined' (and dynamically importing any server-only functions within an if (import.meta.env.SSR) {...} statement) fixed it.