TypeError: Cannot read properties of undefined (reading 'clientModules')

Question

The project's pages work fine with npm run dev and I do not get these errors with the pages with vercel --prod. The problems show up when I generate a production build and run the app with next start.

With [email protected] I got TypeError: Cannot read properties of undefined (reading 'ppr') so I downgraded to [email protected]. Now I am getting multiple instances of TypeError: Cannot read properties of undefined (reading 'clientModules')

TypeError: Cannot read properties of undefined (reading 'clientModules') at u (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:108:22420) at /Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:108:23409 at nk (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:38654) at nC (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:54802) at nk (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:51563) at nC (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:54802) at nw (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:38210) at nk (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:38805) at nC (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:54802) at nk (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:51563) TypeError: Cannot read properties of undefined (reading 'clientModules') at u (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:108:22420) at /Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:108:23409 at nk (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:38654) at nC (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:54802) at nj (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:60948) at AsyncLocalStorage.run (node:async_hooks:346:14) at Timeout._onTimeout (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:76278) at listOnTimeout (node:internal/timers:573:17) at process.processTimers (node:internal/timers:514:7) TypeError: Cannot read properties of undefined (reading 'clientModules') at u (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:108:22420) at /Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:108:23409 at nk (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:38654) at nC (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:54802) at nj (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:60948) at AsyncLocalStorage.run (node:async_hooks:346:14) at Timeout._onTimeout (/Users/donovanwhite/art_folio/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:28:76278) at listOnTimeout (node:internal/timers:573:17) at process.processTimers (node:internal/timers:514:7)

Answer 1

The issue that I had was that my routes were conflicting. I had one folder that was (homepage), meaning that the route was effectively "/". However, I also left a page.tsx file in the root directory, which had "/" as its route as well. Make sure that you don't have any overlap between folders that aren't included in the route structure and their root folders.

Answer 2

I had this problem few days ago, for context i was converting my Vite-React-SPA to NextJS for SSR and SSG, then also host it on Vercel (the Vite version was already hosted).

I found the problem from restructuring the filepaths (I was using App router), then i run debug. It's painful way of doing it yes. but i did found the problem.

on my file arch app/(group_folder)/@footer/page, there was a missing import statement here. AND because it was not in the root app/ where homepage(/page) was located, it causes build error for some reason. So the idea was if you're using @slots then don't put them inside other folders and keep them in the root folder of your pages along with the /page.js*jsx.

like this

~app/page.jsx
~app/@footer/page.jsx
~app/@navigation/page.jsx

that's how i fixed this error

TypeError: Cannot read properties of undefined (reading 'clientModules')

Since Im new to this and don't understand the intricacies of server and client components yet i may be wrong with this approach so if anyone can edit this so its more readable i would be more than glad.