TypeError: Cannot assign to read only property 'params' of object '#<Object>'

[NriotHrreion]

Summary

I have no idea why this error comes in my project. After deleting the build directory and re-running npm run dev, this error will disappear when I open the web page for the first time, but reappear after reloading the page.

The stacktrace:

Additional information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
  Available memory (MB): 32561
  Available CPU cores: 32
Binaries:
  Node: 22.17.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.13.1
Relevant Packages:
  next: 15.5.4 // Latest available version is detected (15.5.4).
  eslint-config-next: 15.3.4
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.8.3
Next.js Config:
  output: export

Example

https://github.com/opanel-mc/opanel/tree/main/frontend

This issue may have something to do with this file: https://github.com/opanel-mc/opanel/blob/f1be02ab930454dad91a5415cda25d8763f83662/frontend/lib/settings.ts

[icyJoseph]

Let's try to discard a Turbopack issue, I don't think it is the issue but, worth trying.

I'll take a look at your repository, unfortunately it is quite large, but let's see.

[icyJoseph]

Kind of weird that this line, https://github.com/opanel-mc/opanel/blob/main/frontend/lib/settings.ts#L5, doesn't crash the entire thing, as it does top-module level window access, without guards.. 🤔

[NriotHrreion]

This nextjs frontend is a pure SSG one, and none of the frontend code would run in nodejs environment in production, so I used window directly.
Is there any better practice to do that? And I don't know whether this is related to the issue.

[NriotHrreion]

Solved.

Final solution:
Use the following code instead of const storage = window.localStorage; at the top level

function getLocalStorage() {
  if(typeof window !== "undefined" && window.localStorage) {
    return window.localStorage;
  }
  throw new Error("localStorage is not defined.");
}

In the functions that need to use localStorage, do:

let storage: Storage;
try {
  storage = getLocalStorage();
} catch {
  return ...;
}
// ...

[icyJoseph]

Oh wow, so I hit the nail first try! Too bad the error message was so cryptic... Good job!