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noLabelVar

src/content/docs/linter/rules/no-label-var.mdx

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

<Tabs> <TabItem label="JavaScript (and super languages)" icon="seti:javascript"> ## Summary - Rule available since: `v1.0.0` - Diagnostic Category: [`lint/suspicious/noLabelVar`](/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 [`no-label-var`](https://eslint.org/docs/latest/rules/no-label-var)

How to configure

json
{
	"linter": {
		"rules": {
			"suspicious": {
				"noLabelVar": "error"
			}
		}
	}
}

Description

Disallow labels that share a name with a variable

Examples

Invalid

js
const x1 = "test";
x1: expr;
<pre class="language-text"><code class="language-text">code-block.js:2:1 <a href="https://biomejs.dev/linter/rules/no-label-var">lint/suspicious/noLabelVar</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">Do not use the </span><span style="color: Tomato;"><strong>x1</strong></span><span style="color: Tomato;"> variable name as a label</span> <strong>1 │ </strong>const x1 = &quot;test&quot;; <strong><span style="color: Tomato;">&gt;</span></strong> <strong>2 │ </strong>x1: expr; <strong> │ </strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong> <strong>3 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">The variable is declared here</span> <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>const x1 = &quot;test&quot;; <strong> │ </strong> <strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong> <strong>2 │ </strong>x1: expr; <strong>3 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Creating a label with the same name as an in-scope variable leads to confusion.</span> </code></pre>

Valid

js
const x = "test";
z: expr;
</TabItem> </Tabs>