Having issues with ignores in v9

[sebnitu]

I'm in the process of migrating over to v9 and am having a hard time getting ignores to work as expected. My old implementation looked like this and it ignored these directories and all of their content:

ignorePatterns: ['dev', 'dist', 'tests', 'tsconfig.json']

In the new flat config file, I converted this to look like:

ignores: [
  '**/dev/*',
  '**/dist/*',
  '**/tests/*',
  'tsconfig.json',
],

but when I run eslint, I get a bunch of errors in files that should be getting ignored. Here are some of my testing to try and figure out how it works:

---

ignores: []

Result: 7465 problems (7465 errors, 0 warnings)

---

ignores: [
  '**/dev/*'
]

Result: 5159 problems (5159 errors, 0 warnings)
Ok, on the right track, lets keep going...

---

ignores: [
  '**/dev/*',
  '**/dist/*'
]

Result: 2157 problems (2157 errors, 0 warnings)
Event better, keep going...

---

ignores: [
  '**/dev/*',
  '**/dist/*',
  '**/tests/*'
]

Result: 2481 problems (2481 errors, 0 warnings)
Wait, what? Why did the number of errors go up after adding another ignore directory?!?

At this point, I can't get the errors to go down anymore and when I look at the first offending file, it's in this directory:

/Users/sebastian/dev/vrembem/packages/vrembem/dist/index.umd.cjs

Why is this file not being ignored with the '**/dist/*' rule?

Incase it matters, my eslint.config.js file is in the root of my project: /Users/sebastian/dev/vrembem/eslint.config.js and according to the docs that's where the globs should be starting at, correct?

[sebnitu]

For whatever reason removing js.configs.recommended from my config fixed my issue:

import js from '@eslint/js';

export default [
  js.configs.recommended,
  {
    // ...
  }
]

I even copy/pasted all the rules from https://www.npmjs.com/package/@eslint/js?activeTab=code into my own config so all the same rules should be applied but it's no longer triggering on files that should be getting ignored. 🤷

[kewisch]

Have you tried putting ignores in a config object by itself? #17429

export default [
  {
    ignores: [
      '**/dev/*',
      '**/dist/*',
      '**/tests/*',
      'tsconfig.json',
    ]
  },
  js.configs.recommended,
  {
    // ...
  }
]

[sebnitu]

Yup, that fixed my issue! I'm still having a hard time wrapping my head around why this worked tho? I've read the docs a few times especially related to Configuration Objects but I still don't think I'm fully wrapping my head around how that works. Does every "config object" cause the linter to run except for these "special" objects that just act as globals? Why doesn't js.configs.recommended also act as a global as well instead of (what I think it's doing) running it's own linting along side my custom object?

Either way, thank you for the suggestion!

[kewisch]

I haven't fully understood it either yet, but here is what I know:

• The ignores by itself is a specical construct to apply global ignores. If you add any other keys, it turns into a normal block and behaves differently.
• Each subsequent block is applied in a cascading manner.
  • So js.configs.recommended provides a set of rules. They will apply to all future config blocks.
  • If you have a next block that has e.g. files in it, it will take whatever came before that, and apply the new rules on top, but only for the files specified. This will propagate to other blocks in the future that affect the same files.
  • The same goes for ignores with other keys. It will apply the new rules to all files, except those in the ignores section.
  • If you have another block after this that doesn't have ignores, it will take the rules from prior blocks where the files were within the selection.

I can imagine that the number went up because the ignores block did its job ignoring the rules, but a subsequent block was then checking the supposedly ignored files with a different combination of enabled rules.