For reference information on these configuration formats, refer to the following documentation:

-[eslintrc configuration files](configuration-files-deprecated)

-[flat configuration files](configuration-files)

-[eslintrc configuration files](configuration-files-deprecated)

-[flat configuration files](configuration-files)

To get started, use the[configuration migrator](https://npmjs.com/package/@eslint/migrate-config) on your existing configuration file (`.eslintrc`,`.eslintrc.json`,`.eslintrc.yml`), like this:

{{ npx_tabs({

package:null,

args:["@eslint/migrate-config", ".eslintrc.json"]

package:"@eslint/migrate-config",

args:[".eslintrc.json"]

}) }}

This will create a starting point for your`eslint.config.js` file but is not guaranteed to work immediately without further modification. It will, however, do most of the conversion work mentioned in this guide automatically.

While the configuration file format has changed from eslintrc to flat config, the following has stayed the same:

-Syntax for configuring rules.

-Syntax for configuring processors.

-The CLI, except for the flag changes noted in[CLI Flag Changes](#cli-flag-changes).

-Global variables are configured the same way, but on a different property (see[Configuring Language Options](#configuring-language-options)).

- Syntax for configuring rules.

- Syntax for configuring processors.

- The CLI, except for the flag changes noted in[CLI Flag Changes](#cli-flag-changes).

- Global variables are configured the same way, but on a different property (see[Configuring Language Options](#configuring-language-options)).

In eslintrc files, use the`extends` property to use predefined and shareable configs. ESLint comes with two predefined configs that you can access as strings:

-`"eslint:recommended"`: the rules recommended by ESLint.

-`"eslint:all"`: all rules shipped with ESLint.

-`"eslint:recommended"`: the rules recommended by ESLint.

-`"eslint:all"`: all rules shipped with ESLint.

You can also use the`extends` property to extend a shareable config. Shareable configs can either be paths to local config files or npm package names.

-`--rulesdir`

-`--ext`

-`--resolve-plugins-relative-to`

-`--rulesdir`

-`--ext`

-`--resolve-plugins-relative-to`

The flag`--no-eslintrc` has been replaced with`--no-config-lookup`.

-The`root` option no longer exists. (Flat config files act as if`root:true` is set.)

-The`files` option cannot be a single string anymore, it must be an array.

-The`sourceType` option now supports the new value`"commonjs"` (`.eslintrc` supports it too, but it was never documented).

- The`root` option no longer exists. (Flat config files act as if`root:true` is set.)

- The`files` option cannot be a single string anymore, it must be an array.

- The`sourceType` option now supports the new value`"commonjs"` (`.eslintrc` supports it too, but it was never documented).