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noUnmatchableAnbSelector

src/content/docs/linter/rules/no-unmatchable-anb-selector.mdx

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import { Tabs, TabItem } from '@astrojs/starlight/components';

<Tabs> <TabItem label="CSS" icon="seti:css"> ## Summary - Rule available since: `v1.8.0` - Diagnostic Category: [`lint/correctness/noUnmatchableAnbSelector`](/reference/diagnostics#diagnostic-category) - This rule is **recommended**, meaning it is enabled by default. - This rule doesn't have a fix. - The default severity of this rule is [**error**](/reference/diagnostics#error). - Sources: - Same as [`selector-anb-no-unmatchable`](https://github.com/stylelint/stylelint/blob/main/lib/rules/selector-anb-no-unmatchable/README.md)

How to configure

json
{
	"linter": {
		"rules": {
			"correctness": {
				"noUnmatchableAnbSelector": "error"
			}
		}
	}
}

Description

Disallow unmatchable An+B selectors.

Selectors that always evaluate to 0 will not match any elements. For more details about the An+B syntax, see: https://www.w3.org/TR/css-syntax-3/#anb-microsyntax

Examples

Invalid

css
a:nth-child(0) {}
<pre class="language-text"><code class="language-text">code-block.css:1:13 <a href="https://biomejs.dev/linter/rules/no-unmatchable-anb-selector">lint/correctness/noUnmatchableAnbSelector</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">This selector will never match any elements.</span> <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>a:nth-child(0) &#123;&#125; <strong> │ </strong> <strong><span style="color: Tomato;">^</span></strong> <strong>2 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Avoid using An+B selectors that always evaluate to 0.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">For more details, see </span><span style="color: lightgreen;"><a href="https://www.w3.org/TR/css-syntax-3/#anb-microsyntax">the official spec for An+B selectors</a></span><span style="color: lightgreen;">.</span> </code></pre>
css
a:nth-last-child(0n) {}
<pre class="language-text"><code class="language-text">code-block.css:1:18 <a href="https://biomejs.dev/linter/rules/no-unmatchable-anb-selector">lint/correctness/noUnmatchableAnbSelector</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">This selector will never match any elements.</span> <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>a:nth-last-child(0n) &#123;&#125; <strong> │ </strong> <strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong> <strong>2 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Avoid using An+B selectors that always evaluate to 0.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">For more details, see </span><span style="color: lightgreen;"><a href="https://www.w3.org/TR/css-syntax-3/#anb-microsyntax">the official spec for An+B selectors</a></span><span style="color: lightgreen;">.</span> </code></pre>
css
a:nth-of-type(0n+0) {}
<pre class="language-text"><code class="language-text">code-block.css:1:15 <a href="https://biomejs.dev/linter/rules/no-unmatchable-anb-selector">lint/correctness/noUnmatchableAnbSelector</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">This selector will never match any elements.</span> <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>a:nth-of-type(0n+0) &#123;&#125; <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>2 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Avoid using An+B selectors that always evaluate to 0.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">For more details, see </span><span style="color: lightgreen;"><a href="https://www.w3.org/TR/css-syntax-3/#anb-microsyntax">the official spec for An+B selectors</a></span><span style="color: lightgreen;">.</span> </code></pre>
css
a:nth-last-of-type(0 of a) {}
<pre class="language-text"><code class="language-text">code-block.css:1:20 <a href="https://biomejs.dev/linter/rules/no-unmatchable-anb-selector">lint/correctness/noUnmatchableAnbSelector</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">This selector will never match any elements.</span> <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>a:nth-last-of-type(0 of a) &#123;&#125; <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>2 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Avoid using An+B selectors that always evaluate to 0.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">For more details, see </span><span style="color: lightgreen;"><a href="https://www.w3.org/TR/css-syntax-3/#anb-microsyntax">the official spec for An+B selectors</a></span><span style="color: lightgreen;">.</span> </code></pre>

Valid

css
a:nth-child(1) {}
css
a:nth-last-child(1n) {}
css
a:nth-of-type(1n+0) {}
css
a:nth-last-of-type(1 of a) {}
</TabItem> </Tabs>