---
url: /docs/guide/usage/linter/rules/eslint/no-self-compare.md
---

### What it does

Disallow comparisons where both sides are exactly the same.

### Why is this bad?

Comparing a variable against itself is usually an error, either a typo or refactoring error.
It is confusing to the reader and may potentially introduce a runtime error.

### Examples

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

```javascript
var x = 10;
if (x === x) {
  x = 20;
}
```

## How to use

## Version

This rule was added in v0.0.3.

## References