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# prefer-exact-props

[Added in v0.9.5](https://github.com/web-infra-dev/rslint/releases/tag/v0.9.5)
## Configuration


```ts title=rslint.config.ts
import { defineConfig, reactPlugin } from '@rslint/core';

export default defineConfig([
  reactPlugin.configs.recommended,
  {
    rules: {
      'react/prefer-exact-props': 'error',
    },
  },
]);
```

Require React `propTypes` definitions to use an exact wrapper.

## Rule Details

This rule reports non-empty `propTypes` objects that are not wrapped by a
function marked with `exact: true` in `settings.propWrapperFunctions`. Empty
objects are allowed.

Configure an exact wrapper in the shared React settings:

```json
{
  "settings": {
    "propWrapperFunctions": [{ "property": "exact", "exact": true }]
  }
}
```

Examples of **incorrect** code for this rule:

```jsx
function Component(props) {
  return <div>{props.name}</div>;
}

Component.propTypes = {
  name: PropTypes.string,
};
```

```jsx
class Component extends React.Component {
  static propTypes = otherWrapper({
    name: PropTypes.string,
  });
}
```

Examples of **correct** code for this rule:

```jsx
function Component(props) {
  return <div>{props.name}</div>;
}

Component.propTypes = exact({
  name: PropTypes.string,
});
```

```jsx
class Component extends React.Component {
  static propTypes = {};
}
```

## Differences from ESLint

- Only assignments to `.propTypes` are checked. Other reads are ignored;
  eslint-plugin-react 7.37.5 may report them or throw while evaluating them.
- Class fields are checked only when they are static and their runtime name is
  `propTypes`. Instance fields, `#private` fields, and TypeScript `props`
  fields are ignored.
- Computed member names are checked only when written as a string or static
  template literal, such as `Component['propTypes']`. Variables used as keys
  are ignored.
- A `propTypes` value referenced through a variable is checked only when the
  variable is a directly initialized `const`. For object literals, every value
  reference must be another `propTypes` assignment; property mutations,
  escapes, other reads, mutable bindings, and destructured bindings are treated
  as unknown.

## Original Documentation

- [eslint-plugin-react: prefer-exact-props](https://github.com/jsx-eslint/eslint-plugin-react/blob/v7.37.5/docs/rules/prefer-exact-props.md)
- [Source code](https://github.com/jsx-eslint/eslint-plugin-react/blob/v7.37.5/lib/rules/prefer-exact-props.js)