deprecated tsconfig settings are used as default (node10?)

[ldeveber]

Link to the code that reproduces this issue

https://github.com/ldeveber/nextjs-tsconfig-example

To Reproduce

1. clone example, npm i
2. run npm run lint (can cancel after output is shown)

❯ npm run lint                                                                             68% 󰂃  08:41 

> lint
> next lint


   We detected TypeScript in your project and reconfigured your tsconfig.json file for you.
   The following suggested values were added to your tsconfig.json. These values can be changed to fit your project's needs:

        - lib was set to dom,dom.iterable,esnext
        - allowJs was set to true
        - noEmit was set to true
        - incremental was set to true
        - include was set to ['next-env.d.ts', '.next/types/**/*.ts', '**/*.ts', '**/*.tsx']
        - plugins was updated to add { name: 'next' }
        - exclude was set to ['node_modules']

   The following mandatory changes were made to your tsconfig.json:

        - esModuleInterop was set to true (requirement for SWC / babel)
        - moduleResolution was set to node (to match webpack resolution)
        - resolveJsonModule was set to true (to match webpack resolution)
        - jsx was set to preserve (next.js implements its own optimized jsx transform)

? How would you like to configure ESLint? https://nextjs.org/docs/app/api-reference/config/eslint

Current vs. Expected behavior

CURRENT BEHAVIOR

Updates tsconfig.json with mandatory features including deprecated ones required by next.

EXPECTED BEHAVIOR

Updates tsconfig.json with mandatory features required by next, excluding deprecated features. According to https://www.typescriptlang.org/tsconfig/#moduleResolution

'node10' (previously called 'node') for Node.js versions older than v10, which only support CommonJS require. You probably won’t need to use node10 in modern code.

Provide environment information

/bin/sh: yarn: command not found

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:26 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T8112
  Available memory (MB): 24576
  Available CPU cores: 8
Binaries:
  Node: 24.1.0
  npm: 11.4.2
  Yarn: N/A
  pnpm: 10.13.1
Relevant Packages:
  next: 15.4.2-canary.15 // Latest available version is detected (15.4.2-canary.15).
  eslint-config-next: N/A
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.8.3
Next.js Config:
  output: N/A

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

TypeScript, Linting, create-next-app

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

next dev (local)

Additional context

I was trying to set up a new app, and I had skipped eslint because I had planned to add biome, but I forgot to change the command before I ran it and saw this by chance.

Note: I did not install the typescript 5.9 beta, but I wanted to surface this because its coming!

https://devblogs.microsoft.com/typescript/announcing-typescript-5-9-beta/

[ldeveber]

Oh forgot to add: the project I was working with locally has "type": "module", in the package.json, but the example template did not. It happened in both!

[ldeveber]

Also added a PR showing the diff in generation from running (if needed) https://github.com/ldeveber/nextjs-tsconfig-example/pull/1/files