Linter errors - "parserOptions.project" has been provided for @typescript-eslint/parser.

[randspy]

Which project does this relate to?

Create Tanstack App

Describe the bug

Hi,

I get lint errors on a generated app without any modifications. Linting in the IDE (Cursor) works correctly.

/Users/sgluter/programming/react/tanstack/test-lint/eslint.config.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): eslint.config.js

/Users/sgluter/programming/react/tanstack/test-lint/prettier.config.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): prettier.config.js

/Users/sgluter/programming/react/tanstack/test-lint/vite.config.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): vite.config.js

✖ 3 problems (3 errors, 0 warnings)

Your Example Website or App

https://github.com/TanStack/create-tsrouter-app/

Steps to Reproduce the Bug or Issue

Run:

$ npx create-tsrouter-app@latest --add-ons
┌ Let's configure your TanStack application
│
◇ What would you like to name your project?
│ test-lint
│
◇ Select the router type:
│ File Router - File-based routing structure
│
◇ Would you like to use Tailwind CSS?
│ No
│
◇ Select toolchain
│ eslint+prettier
│
◇ What add-ons would you like for your project:
│ none
│
◇ Would you like any examples?
│ none
│
◇ Installed dependencies
│
◇ Applied toolchain eslint+prettier
│
◇ Initialized git repository
│
└ Your TanStack app is ready in 'test-lint'.

Use the following commands to start your app:
% cd test-lint
% npm start

Please read the README.md for more information on testing, styling, adding routes, react-query, etc.

$ cd test-lint
$ npm run lint

lint
eslint

Expected behavior

Shouldn't run into errors

Screenshots or Videos

No response

Platform

• OS: macOS Sequoia 15.3.2
• Node: 22.14.0

Additional context

No response

[maksimyaromin]

Hey @randspy,

you can add allowJs: true to your tsconfig.json. That should fix the issue.

---

As a more global solution that would also apply to newly created projects, it might make sense to adjust the config in the @tanstack/eslint-config package — for example, by using projectService instead of project: true or enabling the parser only for TypeScript files. Alternatively, allowJs: true could be included by default when generating a project with the eslint+prettier toolchain via create-tsrouter-app.

[randspy]

Hi @maksimyaromin. Thanks for the suggestion.

Adding allowJs: true has resolved the problem. But caused

eslint.config.js:3:32 - error TS7016: Could not find a declaration file for module '@tanstack/eslint-config'. '/Users/sgluter/programming/react/tanstack/test-lint-4/node_modules/@tanstack/eslint-config/src/index.js' implicitly has an 'any' type. Try npm i --save-dev @types/tanstack__eslint-configif it exists or add a new declaration (.d.ts) file containingdeclare module '@tanstack/eslint-config';`

3 import { tanstackConfig } from '@tanstack/eslint-config'`

for $ npm run build.

Adding a new declaration resolved that problem.
declare module '@tanstack/eslint-config' { export const tanstackConfig: Array<any> }

BR

[maksimyaromin]

Yes, with allowJs: true, all JavaScript files will be treated as part of the project (as they should be). Because of the @ts-check directive in eslint.config.js, type checking fails during build.

The quickest "fix" would be to remove @ts-check from eslint.config.js, which would instantly eliminate the issue. Adding declare module '@tanstack/eslint-config' would also do the trick.

That said, I’m not sure what the original intent behind this setup was — maybe there’s a specific reason for it. In that case, adding allowJs: true might not be the best solution.

If we don’t add allowJs: true, the original issue could potentially be worked around locally by overriding the parser config for JavaScript files in eslint.config.js, like this:

export default [
  ...tanstackConfig,
  {
    files: ['**/*.js'],
    languageOptions: {
      parserOptions: { projectService: { allowDefaultProject: ['*.js'] } },
    },
  },
]

But ideally, this kind of logic should live inside the @tanstack/eslint-config package itself.

Seems like we’ll need to wait for feedback from the create-tsrouter-app maintainers, since there are multiple ways to fix this — it’s just not clear which one aligns best with the original design.

[randspy]

I did some more tests. We have two cases:

The first case is for configurations without TanStack Start, which use Vite.

In the configurations with TanStack Start, where we are using Vinxi, we don't have the declaration issue. However, when we run the linter after the build, we encounter this error.

  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): .output/public/_build/assets/__vite-browser-external-BIHI7g3E.js

/Users/sgluter/programming/react/tanstack/test-lint-7/.output/public/_build/assets/client-DREEvhgA.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): .output/public/_build/assets/client-DREEvhgA.js

/Users/sgluter/programming/react/tanstack/test-lint-7/.output/public/_build/assets/client-hks9yzgi.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): .output/public/_build/assets/client-hks9yzgi.js

/Users/sgluter/programming/react/tanstack/test-lint-7/.output/public/_build/assets/demo.start.api-request-DzKa0PxT.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): .output/public/_build/assets/demo.start.api-request-DzKa0PxT.js

/Users/sgluter/programming/react/tanstack/test-lint-7/.output/public/_build/assets/demo.start.server-funcs-BddGWVTD.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): .output/public/_build/assets/demo.start.server-funcs-BddGWVTD.js

/Users/sgluter/programming/react/tanstack/test-lint-7/.output/public/_build/assets/index-BPu7zSlL.js
  0:0  error  Parsing error: "parserOptions.project" has been provided for @typescript-eslint/parser.
The file was not found in any of the provided project(s): .output/public/_build/assets/index-BPu7zSlL.js

/Users/sgluter/programming/react/tanstack/test-lint-7/.output/server/chunks/nitro/nitro.mjs
   42:5  error  Definition for rule 'unicorn/prefer-at' was not found        unicorn/prefer-at
  586:5  error  Definition for rule 'unicorn/no-array-reduce' was not found  unicorn/no-array-reduce

/Users/sgluter/programming/react/tanstack/test-lint-7/.vinxi/types/nitro-config.d.ts
  0:1  error  This rule requires the `strictNullChecks` compiler option to be turned on to function correctly  @typescript-eslint/no-unnecessary-condition

/Users/sgluter/programming/react/tanstack/test-lint-7/.vinxi/types/nitro-imports.d.ts
  0:1  error  This rule requires the `strictNullChecks` compiler option to be turned on to function correctly  @typescript-eslint/no-unnecessary-condition

/Users/sgluter/programming/react/tanstack/test-lint-7/.vinxi/types/nitro-routes.d.ts
   0:1   error  This rule requires the `strictNullChecks` compiler option to be turned on to function correctly  @typescript-eslint/no-unnecessary-condition
   2:1   error  Expected 1 empty line after import statement not followed by another import                      import/newline-after-import
   7:63  error  `import()` type annotations are forbidden                                                        @typescript-eslint/consistent-type-imports
  10:63  error  `import()` type annotations are forbidden                                                        @typescript-eslint/consistent-type-imports
  13:63  error  `import()` type annotations are forbidden                                                        @typescript-eslint/consistent-type-imports

/Users/sgluter/programming/react/tanstack/test-lint-7/.vinxi/types/nitro.d.ts
  0:1  error  This rule requires the `strictNullChecks` compiler option to be turned on to function correctly  @typescript-eslint/no-unnecessary-condition
  1:1  error  Do not use a triple slash reference for ./nitro-routes.d.ts, use `import` style instead          @typescript-eslint/triple-slash-reference
  2:1  error  Do not use a triple slash reference for ./nitro-config.d.ts, use `import` style instead          @typescript-eslint/triple-slash-reference
  3:1  error  Do not use a triple slash reference for ./nitro-imports.d.ts, use `import` style instead         @typescript-eslint/triple-slash-reference```