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# no-const-assign

[Added in v0.1.14](https://github.com/web-infra-dev/rslint/releases/tag/v0.1.14)
## Configuration

| Preset                   | Configured Value |
| ------------------------ | ---------------- |
| ✅ js.configs.recommended | `"error"`        |


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

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'no-const-assign': 'error',
    },
  },
]);
```

## Rule Details

Disallows reassigning variables declared with `const`, `using`, or `await using`. These constant bindings cannot be reassigned after their initial declaration. Attempting to modify them (via assignment, increment, decrement, or destructuring assignment) is always a mistake and would throw a `TypeError` at runtime.

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

```javascript
const x = 1;
x = 2;

const y = 0;
y++;

const { z } = obj;
z = 3;

const [a, b] = [1, 2];
[a, b] = [3, 4];

using resource = acquireResource();
resource = acquireOtherResource();
```

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

```javascript
const x = 1;
console.log(x);

let y = 0;
y = 1;

const obj = {};
obj.key = 'value'; // mutating properties is fine

using resource = acquireResource();
resource.use();
```

## Original Documentation

- [ESLint: no-const-assign](https://eslint.org/docs/latest/rules/no-const-assign)
- [Source code](https://github.com/eslint/eslint/blob/v10.8.1/lib/rules/no-const-assign.js)