TypeError: selector is not a function

Which project does this relate to?

Start

Describe the bug

This is my first time trying out tanstack start and I run into an issue trying to run the app with pnpm dev.

I chose AI, DB, Form, Query and I also chose Netlify

Here are the logs:

Initially looks like everything is ok

❯ pnpm dev

> tanstack-experiments@ dev /Users/aalmacin/Projects/tanstack-experiments
> vite dev --port 3000

11:48:44 p.m. [vite] ⬥ Netlify Environment loaded
11:48:44 p.m. [vite] ⬥ Netlify Middleware loaded. Emulating features: aiGateway, blobs, edgeFunctions, environmentVariables, functions, geolocation, headers, images, redirects, static.
11:48:44 p.m. [vite] ⬥ Netlify 💭 Linking this project to a Netlify site lets you deploy your site, use any environment variables defined on your team and site and much more. Run npx netlify init to get started.

  VITE v7.3.1  ready in 1831 ms

  ➜  Local:   http://localhost:3000/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help

But I am getting {"status":500,"unhandled":true,"message":"HTTPError"} on the browser when I tried to open http://localhost:3000/. On the terminal it shows:

TypeError: selector is not a function
    at memoizedSelector (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:47:30)
    at /Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:76:26
    at Object.useSyncExternalStore (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:10232:18)
    at process.env.NODE_ENV.exports.useSyncExternalStore (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react@19.2.4/node_modules/react/cjs/react.development.js:1270:34)
    at process.env.NODE_ENV.exports.useSyncExternalStoreWithSelector (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:82:19)
    at useStore (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/@tanstack+react-store@0.9.2_react-dom@19.2.4_react@19.2.4__react@19.2.4/node_modules/@tanstack/react-store/src/useStore.ts:35:28)
    at AIAssistant (/Users/aalmacin/Projects/tanstack-experiments/src/components/demo-AIAssistant.tsx:82:18)
    at Object.react_stack_bottom_frame (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:10288:18)
    at renderWithHooks (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:5298:19)
    at renderElement (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:5733:23)
TypeError: selector is not a function
    at memoizedSelector (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:47:30)
    ... 8 lines matching cause stack trace ...
    at renderElement (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:5733:23) {
  cause: TypeError: selector is not a function
      at memoizedSelector (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:47:30)
      at /Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:76:26
      at Object.useSyncExternalStore (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:10232:18)
      at process.env.NODE_ENV.exports.useSyncExternalStore (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react@19.2.4/node_modules/react/cjs/react.development.js:1270:34)
      at process.env.NODE_ENV.exports.useSyncExternalStoreWithSelector (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/use-sync-external-store@1.6.0_react@19.2.4/node_modules/use-sync-external-store/cjs/use-sync-external-store-shim/with-selector.development.js:82:19)
      at useStore (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/@tanstack+react-store@0.9.2_react-dom@19.2.4_react@19.2.4__react@19.2.4/node_modules/@tanstack/react-store/src/useStore.ts:35:28)
      at AIAssistant (/Users/aalmacin/Projects/tanstack-experiments/src/components/demo-AIAssistant.tsx:82:18)
      at Object.react_stack_bottom_frame (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:10288:18)
      at renderWithHooks (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:5298:19)
      at renderElement (/Users/aalmacin/Projects/tanstack-experiments/node_modules/.pnpm/react-dom@19.2.4_react@19.2.4/node_modules/react-dom/cjs/react-dom-server.node.development.js:5733:23),
  status: 500,
  statusText: undefined,
  headers: undefined,
  data: undefined,
  body: undefined,
  unhandled: true
}

Your Example Website or App

https://github.com/aalmacin/tanstack-experiments

Steps to Reproduce the Bug or Issue

Commands:
Choose Netlify and AI, DB, Form, Query

pnpm create @tanstack/start@latest
pnpm dev

Expected behavior

As a new user, I expect to see the sample home page.

Screenshots or Videos

No response

Platform

Router / Start Version: latest
OS: MacOS Tahoe Version 26.3.1
Chip: Apple M4 Pro
Browser: Chrome
Browser Version: 145.0.7632.160
Bundler: vite
Bundler Version: 7.3.1
Node version: v23.11.0

Additional context

No response

It seems to cli issue. not router.

I ran into this error as well I think it's due to the AI option.
I can reproduce it by running dev with an app I created with nothing but the AI option.
Also not including AI while using other options allow me to run dev without errors so I'd suggest there's something up with AI here.

I did it with:

@tanstack/cli: v0.63.0 (latest)
bun: v1.3.11
OS: MacOS Tahoe 26.3

This was addressed in commit c6bd449 / PR #428 (fix(create): upgrade to Vite 8 and fix useStore selector in AI add-on) on April 11. useStore(showAIAssistant) was changed to useStore(showAIAssistant, (state) => state) so the required selector is provided. The fix is on main and just waiting on a release.

Generated by Claude Code

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TypeError: selector is not a function #412

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TypeError: selector is not a function #412

Description

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jong-kyung commented on Mar 12, 2026

phurytw commented on Apr 5, 2026

tannerlinsley commented on Apr 27, 2026

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