---
url: /rules/no-mutable-property-of-props-interface.md
---

# no-mutable-property-of-props-interface

This rule disallows mutable properties in `Props` interfaces for CDK Constructs or Stacks.
(It prohibits defining properties in an interface whose name ends with "Props" without the `readonly` modifier.)

Specifying mutable properties in `Props` interfaces is not recommended as it can lead to unintended side effects.

***

#### 🔧 How to use

::: code-group

```ts [Oxlint]
// oxlint.config.ts
export default defineConfig({
  // ... some configs
  rules: {
    "awscdk/no-mutable-property-of-props-interface": "error",
  },
});
```

```js [ESLint]
// eslint.config.mjs
export default defineConfig({
  // ... some configs
  rules: {
    "awscdk/no-mutable-property-of-props-interface": "error",
  },
});
```

:::

#### ✅ Correct Example

```ts
import { IBucket } from "aws-cdk-lib/aws-s3";

interface MyConstructProps {
  // ✅ readonly properties are allowed
  readonly bucket: IBucket;
}
```

```ts
import { IBucket } from "aws-cdk-lib/aws-s3";

// ✅ This rule does not apply to interfaces not ending with "Props"
interface MyInterface {
  bucket: IBucket;
}
```

#### ❌ Incorrect Example

```ts
import { IBucket } from "aws-cdk-lib/aws-s3";

interface MyConstructProps {
  // ❌ Properties in "Props" interfaces should be readonly
  bucket: IBucket;
}
```