noUnreachable

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/correctness/noUnreachable`](/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-unreachable`](https://eslint.org/docs/latest/rules/no-unreachable)

How to configure

json

{
	"linter": {
		"rules": {
			"correctness": {
				"noUnreachable": "error"
			}
		}
	}
}

Description

Disallow unreachable code

Examples

Invalid

function example() {
    return;
    neverCalled();
}

<pre class="language-text"><code class="language-text">code-block.js:3:5 <a href="https://biomejs.dev/linter/rules/no-unreachable">lint/correctness/noUnreachable</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ✖ This code will never be reached ... 1 │ function example() { 2 │ return; > 3 │ neverCalled(); │ ^^^^^^^^^^^^^^ 4 │ } 5 │ ℹ ... because this statement will return from the function beforehand 1 │ function example() { > 2 │ return; │ ^^^^^^^ 3 │ neverCalled(); 4 │ } </code></pre>

function example() {
    for(let i = 0; i < 10; ++i) {
        break;
    }
}

<pre class="language-text"><code class="language-text">code-block.js:2:28 <a href="https://biomejs.dev/linter/rules/no-unreachable">lint/correctness/noUnreachable</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ✖ This code will never be reached ... 1 │ function example() { > 2 │ for(let i = 0; i < 10; ++i) { │ ^^^ 3 │ break; 4 │ } ℹ ... because this statement will break the flow of the code beforehand 1 │ function example() { 2 │ for(let i = 0; i < 10; ++i) { > 3 │ break; │ ^^^^^^ 4 │ } 5 │ } </code></pre>

function example() {
    for(const key in value) {
        continue;
        neverCalled();
    }
}

<pre class="language-text"><code class="language-text">code-block.js:4:9 <a href="https://biomejs.dev/linter/rules/no-unreachable">lint/correctness/noUnreachable</a> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ✖ This code will never be reached ... 2 │ for(const key in value) { 3 │ continue; > 4 │ neverCalled(); │ ^^^^^^^^^^^^^^ 5 │ } 6 │ } ℹ ... because this statement will continue the loop beforehand 1 │ function example() { 2 │ for(const key in value) { > 3 │ continue; │ ^^^^^^^^^ 4 │ neverCalled(); 5 │ } </code></pre>

</TabItem> </Tabs>

How to configure

Description

Examples

Invalid

Related links