rt.toLowerCase is not a function on fresh next js init about next.js

[alexanderwford]

Disabling the Console Ninja VS Code Extension fixed this for me.

[ArtemGovorov]

Hi, Console Ninja extension team member here. I can confirm the issue was caused by the patch Console Ninja makes in order to support Next.js. Apologies for the inconvenience caused by the broken patch.

As soon as the issue has been brought up to our attention, we have fixed it in less than an hour, the extension version 1.0.306 should be working with the latest version of Next.js.

@timneutkens The behaviour of patching modules in order to make the extension features work is described in the extension docs. Typically, our patches to other tools are quite small and only include our loader at the start of a tool entry file. Unfortunately, with Next.js that packs its own minified version of webpack, it is slightly harder for us. Regarding the obfuscated code of the extension - while we offer a free version of the tool for everyone, it's a closed source project that also has a commercial Pro edition. And while every closed source software is a potential security risk as it can't be audited, it's worth noting that Wallaby Team (the company behind the extension and a couple more popular dev tools, such as Quokka and Wallaby) has been on the market since early 2015 for ~9.5 years, with over a million of users (both free and paid, including about 100,000 Next.js users in 1.5 years of Console Ninja only) trusting our tools to get more productive.

We have also shipped a new version of the patch that should not break Next.js if it fails to apply and will point to Console Ninja in case of any issues.

[rawic]

Hi,
I am also experiencing this issue with the rt.toLowerCase is not a function error when running yarn dev in a project. Here’s the output from running next info in my environment, which might help in identifying any commonalities causing this problem:

Version: Windows 11 Pro Education
  Available memory (MB): 32702
  Available CPU cores: 16
Binaries:
  Node: 20.11.0
  npm: N/A
  Yarn: 1.22.17
  pnpm: N/A
Relevant Packages:
  next: 14.2.1 // Latest available version is detected (14.2.1).
  eslint-config-next: 14.2.1
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.4.3
Next.js Config:
  output: N/A
Done in 1.84s.

Additionally, I've found that rolling back to Next.js version 14.1.4 resolves this issue.

[timneutkens]

Seems that the Console Ninja extension changes the internals of all frameworks, i.e. it changes Next.js internals to preload code. The code of their extension is heavily mangled and can't be audited -- seems like a security risk.

Was able to confirm it adds additional code to Next.js internals and that's why it's breaking:

To be clear: this is editing your node_modules when you have the extension is running.

That type of changing internals is going to break between any version really, not just for Next.js but for any framework that extension supports.

I'd like to avoid having to add integrity checks for core files to Next.js as it's quite slow. Guess we'll have to add a big warning to Next.js when console ninja is detected 😓

[xspaceboy]

Seems like Next.js 14.2 version doesn't support Console Ninja VS Code Extension.
Oh, Maybe Console Ninja VS Code Extension need to update fit to Next.js 14.2 version.

[pwglownia]

You guys are brilliant, it really seems to be connected to Console Ninja extension.

[ArtemGovorov]

@timneutkens Great idea, thanks! Apart from making sure our patches should not break target tools, we went ahead and added/released the following message to all CLI tools we integrate with:

(the URL describes the behaviour of patching modules, and how to quickly undo it).

[CarrettaRiccardo]

Disabling the Console Ninja VS Code Extension fixed this for me.

After disabling Console Ninja, clean .next and node_modules and reinstall dependencies to work.
It seems like to happen again when installing a new dependency and Console Ninja is enabled.

[kobysysouvanh]

I am also having this issue on 14.2.1

[abdulkareemolumoh]

I am having same issues. I started exprencing it ever since i updated my nextjs to 14.2.1

[jovar-dev]

The same issue. NextJS 14.2.1

[Oelshehawi]

Managed to temp fix it by just going into the bundle5.js file and just replacing rt.toLowerCase() -> rt.toString().toLowerCase()

[madrosir]

The same issue. NextJS 14.2.1

[PolGubau]

I tried to downgrade to 14.0.4 but still happening

Edit by maintainer bot: Comment was automatically minimized because it was considered unhelpful. (If you think this was by mistake, let us know). Please only comment if it adds context to the issue. If you want to express that you have the same problem, use the upvote 👍 on the issue description or subscribe to the issue for updates. Thanks!

[timneutkens]

Hey everyone, I've had a look at the reproduction repository but I'm unable to trigger the same error. We tried both macOS, Windows, and Codesandbox but it doesn't trigger. It'd be helpful to get more information than "same issue" for this, to let people know you're running into the same issue you can use the GitHub 👍 feature. Posting "same issue" is not taken into account when sorting issues by how many people are running into them.

Is everyone that commented on this issue using Windows? Something else? Which version of Node.js? Tip: you can run next info to get this information.

[husen1003]

I am also getting the same issue:

Operating System:
Platform: win32
Arch: x64
Version: Windows 10 Pro
Available memory (MB): 15973
Available CPU cores: 8
Binaries:
Node: 20.11.1
npm: N/A
Yarn: N/A
pnpm: 8.7.5
Relevant Packages:
next: 14.2.1 // Latest available version is detected (14.2.1).
eslint-config-next: 14.2.1
react: 18.2.0
react-dom: 18.2.0
typescript: 5.4.5
Next.js Config:
output: N/A

[Hugo-Delattre]

Additionally, I've found that rolling back to Next.js version 14.1.4 resolves this issue.

I had the same issue on latest version, I confirm that rolling back to Next.js 14.1.4 solved it (thanks Rawic!)

[alexanderwford]

I'm also having this issue

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
  Available memory (MB): 131017
  Available CPU cores: 16
Binaries:
  Node: 21.6.2
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 14.2.1 // Latest available version is detected (14.2.1).
  eslint-config-next: 13.5.6
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.4.5
Next.js Config:
  output: N/A

[Poylar]

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Pro
  Available memory (MB): 16307
  Available CPU cores: 16
Binaries:
  Node: 20.9.0
  npm: N/A
  Yarn: N/A
  pnpm: 8.15.5
Relevant Packages:
  next: 14.2.1 // Latest available version is detected (14.2.1).
  eslint-config-next: 14.2.1
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.4.4
Next.js Config

downgrade to 14.1.2 not fixed the problem, only 14.0.2 fixed

[watercubz]

I have the same error when trying to create an api in version 14.2.1 of nextjs, in the api/hello/hello.ts path it tells me that there was an error with the webpack compiler

[user-222002]

im also facing this issue....

[PrinzEugen39]

Hello, so im new developer here with minimum experience. Can you tell me how to recognize problem like this? Like how did we found that console ninja was the source of this problem

[mohammednazim007]

This issue occurred for console Ninja. Update your vs code extension console Ninja & run again

[AkipTsaqif]

As soon as the issue has been brought up to our attention, we have fixed it in less than an hour, the extension version 1.0.306 should be working with the latest version of Next.js.

Finally thank you! At first I thought this is a Next Js issue since it doesn't mention anything about anything other than the webpack itself.

[timneutkens]

@ArtemGovorov thanks for the additional explanation 🙏 I think it would be very helpful if you add a warning / log somewhere to ensure that people are aware that Console Ninja has edited the internals of a framework and might break the framework. I.e. seems a similar issue happened with SvelteKit and they weren't able to figure out the problem for a while as well: sveltejs/kit#10252

[timneutkens]

Awesome, thank you!

[github-actions]

This closed issue has been automatically locked because it had no new activity for 2 weeks. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.