# Ignoring Code


* [`ignorePatterns` in Config Files](#ignorepatterns-in-config-files)
* [The `.eslintignore` File](#the-eslintignore-file)
* [Using an Alternate File](#using-an-alternate-file)
* [Using eslintIgnore in package.json](#using-eslintignore-in-packagejson)
* [Ignored File Warnings](#ignored-file-warnings)

## `ignorePatterns` in Config Files

You can tell ESLint to ignore specific files and directories using `ignorePatterns` in your config files. `ignorePatterns` patterns follow the same rules as `.eslintignore`. Please see the [the `.eslintignore` file documentation](./ignoring-code.md#the-eslintignore-file) to learn more.

```json
{
    "ignorePatterns": ["temp.js", "**/vendor/*.js"],
    "rules": {
        //...
    }
}
```

* Glob patterns in `ignorePatterns` are relative to the directory that the config file is placed in.
* You cannot write `ignorePatterns` property under `overrides` property.
* Patterns defined in `.eslintignore` take precedence over the `ignorePatterns` property of config files.

If a glob pattern starts with `/`, the pattern is relative to the base directory of the config file. For example, `/foo.js` in `lib/.eslintrc.json` matches to `lib/foo.js` but not `lib/subdir/foo.js`.

If a config is provided via the `--config` CLI option, the ignore patterns that start with `/` in the config are relative to the current working directory rather than the base directory of the given config. For example, if `--config configs/.eslintrc.json` is present, the ignore patterns in the config are relative to `.` rather than `./configs`.

## The `.eslintignore` File

You can tell ESLint to ignore specific files and directories by creating an `.eslintignore` file in your project's root directory. The `.eslintignore` file is a plain text file where each line is a glob pattern indicating which paths should be omitted from linting. For example, the following will omit all JavaScript files:

```text
**/*.js
```

When ESLint is run, it looks in the current working directory to find an `.eslintignore` file before determining which files to lint. If this file is found, then those preferences are applied when traversing directories. Only one `.eslintignore` file can be used at a time, so `.eslintignore` files other than the one in the current working directory will not be used.

Globs are matched using [node-ignore](https://github.com/kaelzhang/node-ignore), so a number of features are available:

* Lines beginning with `#` are treated as comments and do not affect the ignore patterns.
* Paths are relative to the current working directory. This is also true of paths passed in via the `--ignore-pattern` [command](https://eslint.org/docs/user-guide/command-line-interface#--ignore-pattern).
* Lines preceded by `!` are negated patterns that re-include a pattern that was ignored by an earlier pattern.
* Ignore patterns behave according to the `.gitignore` [specification](https://git-scm.com/docs/gitignore).

Of particular note is that like `.gitignore` files, all paths used as patterns for both `.eslintignore` and `--ignore-pattern` must use forward slashes as their path separators.

```text
# Valid
/root/src/*.js

# Invalid
\root\src\*.js
```

Please see [`.gitignore`](https://git-scm.com/docs/gitignore)'s specification for further examples of valid syntax.

In addition to any patterns in the `.eslintignore` file, ESLint always follows a couple of implicit ignore rules even if the `--no-ignore` flag is passed. The implicit rules are as follows:

* `node_modules/` is ignored.
* dot-files (except for `.eslintrc.*`), as well as dot-folders and their contents, are ignored.

There are also some exceptions to these rules:

* If the path to lint is a glob pattern or directory path and contains a dot-folder, all dot-files and dot-folders will be linted. This includes dot-files and dot-folders that are buried deeper in the directory structure.

  For example, `eslint .config/` will lint all dot-folders and dot-files in the `.config` directory, including immediate children as well as children that are deeper in the directory structure.

* If the path to lint is a specific file path and the `--no-ignore` flag has been passed, ESLint will lint the file regardless of the implicit ignore rules.

  For example, `eslint .config/my-config-file.js --no-ignore` will cause `my-config-file.js` to be linted. It should be noted that the same command without the `--no-ignore` line will not lint the `my-config-file.js` file.

* Allowlist and denylist rules specified via `--ignore-pattern` or `.eslintignore` are prioritized above implicit ignore rules.

  For example, in this scenario, `.build/test.js` is the desired file to allowlist. Because all dot-folders and their children are ignored by default, `.build` must first be allowlisted so that eslint becomes aware of its children. Then, `.build/test.js` must be explicitly allowlisted, while the rest of the content is denylisted. This is done with the following `.eslintignore` file:

  ```text
  # Allowlist 'test.js' in the '.build' folder
  # But do not allow anything else in the '.build' folder to be linted
  !.build
  .build/*
  !.build/test.js
  ```

  The following `--ignore-pattern` is also equivalent:

      eslint --ignore-pattern '!.build' --ignore-pattern '.build/*' --ignore-pattern '!.build/test.js' parent-folder/

## Using an Alternate File

If you'd prefer to use a different file than the `.eslintignore` in the current working directory, you can specify it on the command line using the `--ignore-path` option. For example, you can use `.jshintignore` file because it has the same format:

    eslint --ignore-path .jshintignore file.js

You can also use your `.gitignore` file:

    eslint --ignore-path .gitignore file.js

Any file that follows the standard ignore file format can be used. Keep in mind that specifying `--ignore-path` means that any existing `.eslintignore` file will not be used. Note that globbing rules in `.eslintignore` follow those of `.gitignore`.

## Using eslintIgnore in package.json

If an `.eslintignore` file is not found and an alternate file is not specified, ESLint will look in package.json for an `eslintIgnore` key to check for files to ignore.

    {
      "name": "mypackage",
      "version": "0.0.1",
      "eslintConfig": {
          "env": {
              "browser": true,
              "node": true
          }
      },
      "eslintIgnore": ["hello.js", "world.js"]
    }

## Ignored File Warnings

When you pass directories to ESLint, files and directories are silently ignored. If you pass a specific file to ESLint, then you will see a warning indicating that the file was skipped. For example, suppose you have an `.eslintignore` file that looks like this:

```text
foo.js
```

And then you run:

    eslint foo.js

You'll see this warning:

```text
foo.js
  0:0  warning  File ignored because of a matching ignore pattern. Use "--no-ignore" to override.

✖ 1 problem (0 errors, 1 warning)
```

This message occurs because ESLint is unsure if you wanted to actually lint the file or not. As the message indicates, you can use `--no-ignore` to omit using the ignore rules.

Consider another scenario where you may want to run ESLint on a specific dot-file or dot-folder, but have forgotten to specifically allow those files in your `.eslintignore` file. You would run something like this:

    eslint .config/foo.js

You would see this warning:

```text
.config/foo.js
  0:0  warning  File ignored by default.  Use a negated ignore pattern (like "--ignore-pattern '!<relative/path/to/filename>'") to override

✖ 1 problem (0 errors, 1 warning)
```

This message occurs because, normally, this file would be ignored by ESLint's implicit ignore rules (as mentioned above). A negated ignore rule in your `.eslintignore` file would override the implicit rule and reinclude this file for linting. Additionally, in this specific case, `--no-ignore` could be used to lint the file as well.