---
url: /docs/guide/usage/linter/rules/eslint/no-constant-condition.md
---

### What it does

Disallow constant expressions in conditions.

### Why is this bad?

A constant expression (for example, a literal) as a test condition might
be a typo or development trigger for a specific behavior.

This rule disallows constant expressions in the test condition of:

* `if`, `for`, `while`, or `do...while` statement
* `?`: ternary expression

### Examples

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

```js
if (false) {
  doSomethingUnfinished();
}

if (new Boolean(x)) {
  doSomethingAlways();
}
if ((x ||= true)) {
  doSomethingAlways();
}

do {
  doSomethingForever();
} while ((x = -1));
```

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

```js
if (x === 0) {
  doSomething();
}

while (typeof x === "undefined") {
  doSomething();
}
```

## Configuration

This rule accepts a configuration object with the following properties:

### checkLoops

type: `boolean | "all" | "allExceptWhileTrue" | "none"`

## How to use

## Version

This rule was added in v0.0.3.

## References