---
description: 'Enforce dot notation whenever possible.'
---

import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

> 🛑 This file is source code, not the primary documentation location! 🛑
>
> See **https://typescript-eslint.io/rules/dot-notation** for documentation.

It adds:

- Support for optionally ignoring computed `private` and/or `protected` member access.
- Compatibility with TypeScript's `noPropertyAccessFromIndexSignature` option.

## Options

This rule adds the following options:

```ts
interface Options extends BaseDotNotationOptions {
  allowPrivateClassPropertyAccess?: boolean;
  allowProtectedClassPropertyAccess?: boolean;
  allowIndexSignaturePropertyAccess?: boolean;
}

const defaultOptions: Options = {
  ...baseDotNotationDefaultOptions,
  allowPrivateClassPropertyAccess: false,
  allowProtectedClassPropertyAccess: false,
  allowIndexSignaturePropertyAccess: false,
};
```

If the TypeScript compiler option `noPropertyAccessFromIndexSignature` is set to `true`, then this rule always allows the use of square bracket notation to access properties of types that have a `string` index signature, even if `allowIndexSignaturePropertyAccess` is `false`.

### `allowPrivateClassPropertyAccess`

{/* insert option description */}

This can be useful because TypeScript will report a type error on dot notation but not array notation.

Example of a correct code when `allowPrivateClassPropertyAccess` is set to `true`:

```ts option='{ "allowPrivateClassPropertyAccess": true }' showPlaygroundButton
class X {
  private priv_prop = 123;
}

const x = new X();
x['priv_prop'] = 123;
```

### `allowProtectedClassPropertyAccess`

{/* insert option description */}

This can be useful because TypeScript will report a type error on dot notation but not array notation.

Example of a correct code when `allowProtectedClassPropertyAccess` is set to `true`:

```ts option='{ "allowProtectedClassPropertyAccess": true }' showPlaygroundButton
class X {
  protected protected_prop = 123;
}

const x = new X();
x['protected_prop'] = 123;
```

### `allowIndexSignaturePropertyAccess`

{/* insert option description */}

Example of correct code when `allowIndexSignaturePropertyAccess` is set to `true`:

```ts option='{ "allowIndexSignaturePropertyAccess": true }' showPlaygroundButton
class X {
  [key: string]: number;
}

const x = new X();
x['hello'] = 123;
```

If the TypeScript compiler option `noPropertyAccessFromIndexSignature` is set to `true`, then the above code is always allowed, even if `allowIndexSignaturePropertyAccess` is `false`.

## When Not To Use It

If you specifically want to use both member access kinds for stylistic reasons, or don't wish to enforce one style over the other, you can avoid this rule.

However, keep in mind that inconsistent style can harm readability in a project.
We recommend picking a single option for this rule that works best for your project.
