---
# Don't modify this file manually. This file is auto generated from source, and you will lose your changes next time the website is built.
# Head to the `biomejs/biome` repository, and modify the source code in there.

title: noUselessTernary
description: Learn more about noUselessTernary
---
import { Tabs, TabItem } from '@astrojs/starlight/components';

<Tabs>
<TabItem label="JavaScript (and super languages)" icon="seti:javascript">
## Summary
- Rule available since: `v1.5.0`
- Diagnostic Category: [`lint/complexity/noUselessTernary`](/reference/diagnostics#diagnostic-category)
- This rule is **recommended**, meaning it is enabled by default.
- This rule has an [**unsafe**](/linter/#unsafe-fixes) fix.
- The default severity of this rule is [**information**](/reference/diagnostics#information).
- Sources: 
  - Same as [`no-unneeded-ternary`](https://eslint.org/docs/latest/rules/no-unneeded-ternary)

## How to configure
```json title="biome.json"
{
	"linter": {
		"rules": {
			"complexity": {
				"noUselessTernary": "error"
			}
		}
	}
}

```
## Description
Disallow ternary operators when simpler alternatives exist.

It’s a common mistake in JavaScript to use a conditional expression to select between two
boolean values instead of using the logical NOT (`!`) or double NOT (`!!`) to convert the test to a boolean.

## Examples

### Invalid

```js
var a = x ? true : true;
```

<pre class="language-text"><code class="language-text">code-block.js:1:9 <a href="https://biomejs.dev/linter/rules/no-useless-ternary">lint/complexity/noUselessTernary</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━<br /><br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unnecessary use of boolean literals in conditional expression.</span><br />  <br />  <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>var a = x ? true : true;<br />   <strong>   │ </strong>        <strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><br />    <strong>2 │ </strong><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Simplify your code by directly assigning the result without using a ternary operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">If your goal is negation, you may use the logical NOT (!) or double NOT (!!) operator for clearer and concise code.<br /></span>    <span style="color: lightgreen;"> Check for more details about </span><span style="color: lightgreen;"><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_NOT">NOT</a></span><span style="color: lightgreen;"> operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unsafe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the conditional expression with</span><br />  <br />  <strong>  1 │ </strong>var<span style="opacity: 0.8;">·</span>a<span style="opacity: 0.8;">·</span>=<span style="opacity: 0.8;">·</span><span style="color: Tomato;">x</span><span style="opacity: 0.8;"><span style="color: Tomato;">·</span></span><span style="color: Tomato;">?</span><span style="opacity: 0.8;"><span style="color: Tomato;">·</span></span><span style="color: Tomato;">t</span><span style="color: Tomato;">r</span><span style="color: Tomato;">u</span><span style="color: Tomato;">e</span><span style="opacity: 0.8;"><span style="color: Tomato;">·</span></span><span style="color: Tomato;">:</span><span style="opacity: 0.8;"><span style="color: Tomato;">·</span></span>true;<br />  <strong>    │ </strong>        <span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span><span style="color: Tomato;">-</span>     <br /></code></pre>

```js
var a = foo === 1 ? false : true;
```

<pre class="language-text"><code class="language-text">code-block.js:1:9 <a href="https://biomejs.dev/linter/rules/no-useless-ternary">lint/complexity/noUselessTernary</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━<br /><br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unnecessary use of boolean literals in conditional expression.</span><br />  <br />  <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>var a = foo === 1 ? false : true;<br />   <strong>   │ </strong>        <strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><br />    <strong>2 │ </strong><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Simplify your code by directly assigning the result without using a ternary operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">If your goal is negation, you may use the logical NOT (!) or double NOT (!!) operator for clearer and concise code.<br /></span>    <span style="color: lightgreen;"> Check for more details about </span><span style="color: lightgreen;"><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_NOT">NOT</a></span><span style="color: lightgreen;"> operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unsafe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the conditional expression with</span><br />  <br />    <strong>1</strong>  <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;">v</span><span style="color: Tomato;">a</span><span style="color: Tomato;">r</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">a</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">=</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">f</span><span style="color: Tomato;">o</span><span style="color: Tomato;">o</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><strong>=</strong></span><span style="color: Tomato;">=</span><span style="color: Tomato;">=</span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;">1</span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>?</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>f</strong></span><span style="color: Tomato;"><strong>a</strong></span><span style="color: Tomato;"><strong>l</strong></span><span style="color: Tomato;"><strong>s</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>:</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>u</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;">;</span><br />      <strong>1</strong><strong> │ </strong><span style="color: MediumSeaGreen;">+</span> <span style="color: MediumSeaGreen;">v</span><span style="color: MediumSeaGreen;">a</span><span style="color: MediumSeaGreen;">r</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">a</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">=</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">f</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>!</strong></span><span style="color: MediumSeaGreen;">=</span><span style="color: MediumSeaGreen;">=</span><span style="color: MediumSeaGreen;">1</span><span style="color: MediumSeaGreen;">;</span><br />    <strong>2</strong> <strong>2</strong><strong> │ </strong>  <br />  <br /></code></pre>

```js
var a = foo + 1 ? false : true;
```

<pre class="language-text"><code class="language-text">code-block.js:1:9 <a href="https://biomejs.dev/linter/rules/no-useless-ternary">lint/complexity/noUselessTernary</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━<br /><br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unnecessary use of boolean literals in conditional expression.</span><br />  <br />  <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>var a = foo + 1 ? false : true;<br />   <strong>   │ </strong>        <strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><br />    <strong>2 │ </strong><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Simplify your code by directly assigning the result without using a ternary operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">If your goal is negation, you may use the logical NOT (!) or double NOT (!!) operator for clearer and concise code.<br /></span>    <span style="color: lightgreen;"> Check for more details about </span><span style="color: lightgreen;"><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_NOT">NOT</a></span><span style="color: lightgreen;"> operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unsafe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the conditional expression with</span><br />  <br />    <strong>1</strong>  <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;">v</span><span style="color: Tomato;">a</span><span style="color: Tomato;">r</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">a</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">=</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">f</span><span style="color: Tomato;">o</span><span style="color: Tomato;">o</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">+</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">1</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><strong>?</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>f</strong></span><span style="color: Tomato;"><strong>a</strong></span><span style="color: Tomato;"><strong>l</strong></span><span style="color: Tomato;"><strong>s</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>:</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>u</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;">;</span><br />      <strong>1</strong><strong> │ </strong><span style="color: MediumSeaGreen;">+</span> <span style="color: MediumSeaGreen;">v</span><span style="color: MediumSeaGreen;">a</span><span style="color: MediumSeaGreen;">r</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">a</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">=</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>!</strong></span><span style="color: MediumSeaGreen;"><strong>(</strong></span><span style="color: MediumSeaGreen;">f</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">+</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">1</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>)</strong></span><span style="color: MediumSeaGreen;">;</span><br />    <strong>2</strong> <strong>2</strong><strong> │ </strong>  <br />  <br /></code></pre>

```js
var a = foo + 1 ? true : false;
```

<pre class="language-text"><code class="language-text">code-block.js:1:9 <a href="https://biomejs.dev/linter/rules/no-useless-ternary">lint/complexity/noUselessTernary</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━<br /><br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unnecessary use of boolean literals in conditional expression.</span><br />  <br />  <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>var a = foo + 1 ? true : false;<br />   <strong>   │ </strong>        <strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><br />    <strong>2 │ </strong><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Simplify your code by directly assigning the result without using a ternary operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">If your goal is negation, you may use the logical NOT (!) or double NOT (!!) operator for clearer and concise code.<br /></span>    <span style="color: lightgreen;"> Check for more details about </span><span style="color: lightgreen;"><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_NOT">NOT</a></span><span style="color: lightgreen;"> operator.</span><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Unsafe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the conditional expression with</span><br />  <br />    <strong>1</strong>  <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;">v</span><span style="color: Tomato;">a</span><span style="color: Tomato;">r</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">a</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">=</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">f</span><span style="color: Tomato;">o</span><span style="color: Tomato;">o</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">+</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">1</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><strong>?</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>u</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>:</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>f</strong></span><span style="color: Tomato;"><strong>a</strong></span><span style="color: Tomato;"><strong>l</strong></span><span style="color: Tomato;"><strong>s</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;">;</span><br />      <strong>1</strong><strong> │ </strong><span style="color: MediumSeaGreen;">+</span> <span style="color: MediumSeaGreen;">v</span><span style="color: MediumSeaGreen;">a</span><span style="color: MediumSeaGreen;">r</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">a</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">=</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>!</strong></span><span style="color: MediumSeaGreen;"><strong>!</strong></span><span style="color: MediumSeaGreen;"><strong>(</strong></span><span style="color: MediumSeaGreen;">f</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">+</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">1</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>)</strong></span><span style="color: MediumSeaGreen;">;</span><br />    <strong>2</strong> <strong>2</strong><strong> │ </strong>  <br />  <br /></code></pre>

### Valid

```js
var a = x === 2 ? 'Yes' : 'No';
```

```js
var a = x === 2 ? 'Yes' : false;
```

## Resources

Logical NOT: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_NOT

## Related links

- [Disable a rule](/linter/#disable-a-rule)
- [Configure the code fix](/linter#configure-the-code-fix)
- [Rule options](/linter/#rule-options)
- [Source Code](https://github.com/biomejs/biome/blob/main/crates/biome_js_analyze/src/lint/complexity/no_useless_ternary.rs)
- [Test Cases](https://github.com/biomejs/biome/blob/main/crates/biome_js_analyze/tests/specs/complexity/noUselessTernary)

</TabItem>
</Tabs>