"With statement are not allowed in strict mode"

[headline-design]

Link to the code that reproduces this issue

https://github.com/headline-design/min-repro

To Reproduce

Start application in development

Current vs. Expected behavior

This is a new issue that did not exist in Next 13.4. I believe the error has something to do with ESM bundling but I may be wrong. The error effects all users that rely on Turndown for ProseMirror/TipTap serialization. I believe the error can be resolved with a next/config flag but I may be wrong. Here is a link to the discussion on Turndown - mixmark-io/turndown#378.

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Pro
Binaries:
  Node: 18.17.0
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 14.0.4-canary.43
  eslint-config-next: 14.0.3
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.3.2
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

App Router, ESLint (eslint-config-next), MDX (@next/mdx), TypeScript (plugin, built-in types)

Additional context

Reproduction with create-next-app latest Canary but issue on any build w/ Next + 13.4.