---
url: /docs/guide/usage/linter/rules/typescript/no-useless-default-assignment.md
---

### What it does

Disallow default assignments that can never be used.

### Why is this bad?

A default assignment is redundant when the value can never be `undefined`.
This adds runtime logic and noise without changing behavior.

### Examples

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

```ts
[1, 2, 3].map((a = 0) => a + 1);
```

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

```ts
[1, 2, 3].map((a) => a + 1);
```

## How to use

## Version

This rule was added in v1.49.0.

## References