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noUselessReturn

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

<Tabs> <TabItem label="JavaScript (and super languages)" icon="seti:javascript"> :::caution This rule is part of the [nursery](/linter/#nursery) group. This means that it is experimental and the behavior can change at any time. ::: ## Summary - Rule available since: `v2.3.15` - Diagnostic Category: [`lint/nursery/noUselessReturn`](/reference/diagnostics#diagnostic-category) - This rule has a [**safe**](/linter/#safe-fixes) fix. - The default severity of this rule is [**information**](/reference/diagnostics#information). - Sources: - Inspired from [`no-useless-return`](https://eslint.org/docs/latest/rules/no-useless-return)

How to configure

json
{
	"linter": {
		"rules": {
			"nursery": {
				"noUselessReturn": "error"
			}
		}
	}
}

Description

Disallow redundant return statements.

A return; statement with nothing after it is redundant when it is the last reachable statement in a function body. Removing it does not change the function's behavior, as execution naturally falls through to the end.

Examples

Invalid

js
function foo() {
    return;
}
<pre class="language-text"><code class="language-text">code-block.js:2:5 <a href="https://biomejs.dev/linter/rules/no-useless-return">lint/nursery/noUselessReturn</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">This </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement is unnecessary.</span> <strong>1 │ </strong>function foo() &#123; <strong><span style="color: Tomato;">&gt;</span></strong> <strong>2 │ </strong> return; <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>3 │ </strong>&#125; <strong>4 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Removing this statement does not change the control flow of the function.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit </span><span style="color: lightgreen;"><a href="https://biomejs.dev/linter/#nursery">https://biomejs.dev/linter/#nursery</a></span><span style="color: lightgreen;"> for more information.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Safe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the unnecessary </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement.</span> <strong>1</strong> <strong>1</strong><strong> │ </strong> function foo() &#123; <strong>2</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>u</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>n</strong></span><span style="color: Tomato;"><strong>;</strong></span> <strong>3</strong> <strong>2</strong><strong> │ </strong> &#125; <strong>4</strong> <strong>3</strong><strong> │ </strong> </code></pre>
js
function foo() {
    doSomething();
    return;
}
<pre class="language-text"><code class="language-text">code-block.js:3:5 <a href="https://biomejs.dev/linter/rules/no-useless-return">lint/nursery/noUselessReturn</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">This </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement is unnecessary.</span> <strong>1 │ </strong>function foo() &#123; <strong>2 │ </strong> doSomething(); <strong><span style="color: Tomato;">&gt;</span></strong> <strong>3 │ </strong> return; <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>4 │ </strong>&#125; <strong>5 │ </strong> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Removing this statement does not change the control flow of the function.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit </span><span style="color: lightgreen;"><a href="https://biomejs.dev/linter/#nursery">https://biomejs.dev/linter/#nursery</a></span><span style="color: lightgreen;"> for more information.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Safe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the unnecessary </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement.</span> <strong>1</strong> <strong>1</strong><strong> │ </strong> function foo() &#123; <strong>2</strong> <strong>2</strong><strong> │ </strong> doSomething(); <strong>3</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>u</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>n</strong></span><span style="color: Tomato;"><strong>;</strong></span> <strong>4</strong> <strong>3</strong><strong> │ </strong> &#125; <strong>5</strong> <strong>4</strong><strong> │ </strong> </code></pre>
js
function foo() {
    if (condition) {
        bar();
        return;
    }
}
<pre class="language-text"><code class="language-text">code-block.js:4:9 <a href="https://biomejs.dev/linter/rules/no-useless-return">lint/nursery/noUselessReturn</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">This </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement is unnecessary.</span> <strong>2 │ </strong> if (condition) &#123; <strong>3 │ </strong> bar(); <strong><span style="color: Tomato;">&gt;</span></strong> <strong>4 │ </strong> return; <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>5 │ </strong> &#125; <strong>6 │ </strong>&#125; <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Removing this statement does not change the control flow of the function.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit </span><span style="color: lightgreen;"><a href="https://biomejs.dev/linter/#nursery">https://biomejs.dev/linter/#nursery</a></span><span style="color: lightgreen;"> for more information.</span> <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Safe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Remove the unnecessary </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement.</span> <strong>2</strong> <strong>2</strong><strong> │ </strong> if (condition) &#123; <strong>3</strong> <strong>3</strong><strong> │ </strong> bar(); <strong>4</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>u</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>n</strong></span><span style="color: Tomato;"><strong>;</strong></span> <strong>5</strong> <strong>4</strong><strong> │ </strong> &#125; <strong>6</strong> <strong>5</strong><strong> │ </strong> &#125; </code></pre>

Valid

js
function foo() {
    return 5;
}
js
function foo() {
    if (condition) {
        return;
    }
    bar();
}
js
function foo() {
    for (const x of xs) {
        return;
    }
}
</TabItem> </Tabs>