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useConsistentArrowReturn

src/content/docs/linter/rules/use-consistent-arrow-return.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: `v2.2.3` - Diagnostic Category: [`lint/style/useConsistentArrowReturn`](/reference/diagnostics#diagnostic-category) - This rule isn't recommended, so you need to enable it. - This rule has a [**safe**](/linter/#safe-fixes) fix. - The default severity of this rule is [**information**](/reference/diagnostics#information). - Sources: - Same as [`arrow-body-style`](https://eslint.org/docs/latest/rules/arrow-body-style)

How to configure

json
{
	"linter": {
		"rules": {
			"style": {
				"useConsistentArrowReturn": "error"
			}
		}
	}
}

Description

Enforce consistent arrow function bodies.

This rule enforces the use of arrow functions with no body block when the function body consists of a single return statement. This rule does not report when:

  • the function body contains directives (e.g. "use strict"), or
  • the body (or its descendants) contain comments, or
  • the single return has no argument (return;).

The fix wraps expressions in parentheses when required for correctness (e.g. object literals and sequence expressions).

Examples

Invalid

js
 const bar = () => {
     return {
         bar: {
             foo: 1,
             bar: 2,
         }
     };
 };
<pre class="language-text"><code class="language-text">code-block.js:1:14 <a href="https://biomejs.dev/linter/rules/use-consistent-arrow-return">lint/style/useConsistentArrowReturn</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">The body of this arrow function contains a single </span><span style="color: lightgreen;"><strong>return</strong></span><span style="color: lightgreen;"> statement.</span> <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong> const bar = () =&gt; &#123; <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;">&gt;</span></strong> <strong>2 │ </strong> return &#123; <strong><span style="color: Tomato;">&gt;</span></strong> <strong>3 │ </strong> bar: &#123; <strong><span style="color: Tomato;">&gt;</span></strong> <strong>4 │ </strong> foo: 1, <strong><span style="color: Tomato;">&gt;</span></strong> <strong>5 │ </strong> bar: 2, <strong><span style="color: Tomato;">&gt;</span></strong> <strong>6 │ </strong> &#125; <strong><span style="color: Tomato;">&gt;</span></strong> <strong>7 │ </strong> &#125;; <strong><span style="color: Tomato;">&gt;</span></strong> <strong>8 │ </strong> &#125;; <strong> │ </strong> <strong><span style="color: Tomato;">^</span></strong> <strong>9 │ </strong> <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 return statement.</span> <strong>1</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">c</span><span style="color: Tomato;">o</span><span style="color: Tomato;">n</span><span style="color: Tomato;">s</span><span style="color: Tomato;">t</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">b</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;">=</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">(</span><span style="color: Tomato;">)</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">=</span><span style="color: Tomato;">&gt;</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><strong>&#123;</strong></span> <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;"><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;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;">&#123;</span> <strong>1</strong><strong> │ </strong><span style="color: MediumSeaGreen;">+</span> <span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">c</span><span style="color: MediumSeaGreen;">o</span><span style="color: MediumSeaGreen;">n</span><span style="color: MediumSeaGreen;">s</span><span style="color: MediumSeaGreen;">t</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">b</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;">=</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">(</span><span style="color: MediumSeaGreen;">)</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">=</span><span style="color: MediumSeaGreen;">&gt;</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>(</strong></span><span style="color: MediumSeaGreen;">&#123;</span> <strong>3</strong> <strong>2</strong><strong> │ </strong> bar: &#123; <strong>4</strong> <strong>3</strong><strong> │ </strong> foo: 1, <strong>5</strong> <strong>4</strong><strong> │ </strong> bar: 2, <strong>6</strong> <strong>5</strong><strong> │ </strong> &#125; <strong>7</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">&#125;</span><span style="color: Tomato;"><strong>;</strong></span> <strong>8</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;"><strong>&#125;</strong></span><span style="color: Tomato;">;</span> <strong>6</strong><strong> │ </strong><span style="color: MediumSeaGreen;">+</span> <span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">&#125;</span><span style="color: MediumSeaGreen;"><strong>)</strong></span><span style="color: MediumSeaGreen;">;</span> <strong>9</strong> <strong>7</strong><strong> │ </strong> </code></pre>

Valid

js
const foo = () => 0;
const bar = () => { "use strict"; return 1 }
const baz = () => { /* intentional */ return x }
const qux = () => ({ a: 1 })   // already concise with parens
</TabItem> </Tabs>