t `Record<string, never>` instead.',
      '- If you really want a type meaning "any non-nullish value", you probably want `NonNullable<unknown>` instead.',
    ].join('\n'),
    suggest: [
      'object',
      'unknown',
      'Record<string, never>',
      'NonNullable<unknown>',
    ],
  },
};
```

</details>

### `types`

An object whose keys are the types you want to ban, and the values are error messages.

The type can either be a type name literal (`Foo`), a type name with generic parameter instantiation(s) (`Foo<Bar>`), the empty object literal (`{}`), or the empty tuple type (`[]`).

The values can be:

- A string, which is the error message to be reported; or
- `false` to specifically un-ban this type (useful when you are using `extendDefaults`); or
- An object with the following properties:
  - `message: string` - the message to display when the type is matched.
  - `fixWith?: string` - a string to replace the banned type with when the fixer is run. If this is omitted, no fix will be done.
  - `suggest?: string[]` - a list of suggested replacements for the banned type.

### `extendDefaults`

If you're specifying custom `types`, you can set this to `true` to extend the default `types` configuration. This is a convenience option to save you copying across the defaults when adding another type.

If this is `false`, the rule will _only_ use the types defined in your configuration.

Example configuration:

```jsonc
{
  "@typescript-eslint/ban-types": [
    "error",
    {
      "types": {
        // add a custom message to help explain why not to use it
        "Foo": "Don't use Foo because it is unsafe",

        // add a custom message, AND tell the plugin how to fix it
        "OldAPI": {
          "message": "Use NewAPI instead",
          "fixWith": "NewAPI"
        },

        // un-ban a type that's banned by default
        "{}": false
      },
      "extendDefaults": true
    }
  ]
}
```