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Lint Rule noUselessEmptyExport

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noUselessEmptyExport (since vnext)

Disallow empty exports that don't change anything in a module file.

An empty export {} is sometimes useful to turn a file that would otherwise be a script into a module. Per the TypeScript Handbook Modules page:

In TypeScript, just as in ECMAScript 2015, any file containing a top-level import or export is considered a module. Conversely, a file without any top-level import or export declarations is treated as a script whose contents are available in the global scope.

However, an export {} statement does nothing if there are any other top-level import or export in the file.

Source: https://typescript-eslint.io/rules/no-useless-empty-export/

Examples

Invalid

jsx
import { A } from "module";
export {};
<pre class="language-text"><code class="language-text">nursery/noUselessEmptyExport.js:2:1 <a href="https://docs.rome.tools/lint/rules/noUselessEmptyExport">lint/nursery/noUselessEmptyExport</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;"> </span></strong><strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">This empty </span><span style="color: Tomato;"><strong>export</strong></span><span style="color: Tomato;"> is useless because there's another </span><span style="color: Tomato;"><strong>export</strong></span><span style="color: Tomato;"> or </span><span style="color: Tomato;"><strong>import</strong></span><span style="color: Tomato;">.</span> <strong>1 │ </strong>import { A } from &quot;module&quot;; <strong><span style="color: Tomato;"> </span></strong><strong><span style="color: Tomato;">&gt;</span></strong> <strong>2 │ </strong>export {}; <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;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong> <strong>3 │ </strong> <strong><span style="color: rgb(38, 148, 255);"> </span></strong><strong><span style="color: rgb(38, 148, 255);">ℹ</span></strong> <span style="color: rgb(38, 148, 255);">This </span><span style="color: rgb(38, 148, 255);"><strong>import</strong></span><span style="color: rgb(38, 148, 255);"> makes useless the empty export.</span> <strong><span style="color: Tomato;"> </span></strong><strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>import { A } from &quot;module&quot;; <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>export {}; <strong>3 │ </strong> <strong><span style="color: rgb(38, 148, 255);"> </span></strong><strong><span style="color: rgb(38, 148, 255);">ℹ</span></strong> <span style="color: rgb(38, 148, 255);">Safe fix</span><span style="color: rgb(38, 148, 255);">: </span><span style="color: rgb(38, 148, 255);">Remove this useless empty export.</span> <strong>1</strong> <strong>1</strong><strong> │ </strong> import { A } from &quot;module&quot;; <strong>2</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><strong>x</strong></span><span style="color: Tomato;"><strong>p</strong></span><span style="color: Tomato;"><strong>o</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>{</strong></span><span style="color: Tomato;"><strong>}</strong></span><span style="color: Tomato;"><strong>;</strong></span> <strong>3</strong> <strong>2</strong><strong> │ </strong> </code></pre>
jsx
export const A = 0;
export {};
<pre class="language-text"><code class="language-text">nursery/noUselessEmptyExport.js:2:1 <a href="https://docs.rome.tools/lint/rules/noUselessEmptyExport">lint/nursery/noUselessEmptyExport</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━ <strong><span style="color: Tomato;"> </span></strong><strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">This empty </span><span style="color: Tomato;"><strong>export</strong></span><span style="color: Tomato;"> is useless because there's another </span><span style="color: Tomato;"><strong>export</strong></span><span style="color: Tomato;"> or </span><span style="color: Tomato;"><strong>import</strong></span><span style="color: Tomato;">.</span> <strong>1 │ </strong>export const A = 0; <strong><span style="color: Tomato;"> </span></strong><strong><span style="color: Tomato;">&gt;</span></strong> <strong>2 │ </strong>export {}; <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;">^</span></strong><strong><span style="color: Tomato;">^</span></strong><strong><span style="color: Tomato;">^</span></strong> <strong>3 │ </strong> <strong><span style="color: rgb(38, 148, 255);"> </span></strong><strong><span style="color: rgb(38, 148, 255);">ℹ</span></strong> <span style="color: rgb(38, 148, 255);">This </span><span style="color: rgb(38, 148, 255);"><strong>export</strong></span><span style="color: rgb(38, 148, 255);"> makes useless the empty export.</span> <strong><span style="color: Tomato;"> </span></strong><strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>export const A = 0; <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>export {}; <strong>3 │ </strong> <strong><span style="color: rgb(38, 148, 255);"> </span></strong><strong><span style="color: rgb(38, 148, 255);">ℹ</span></strong> <span style="color: rgb(38, 148, 255);">Safe fix</span><span style="color: rgb(38, 148, 255);">: </span><span style="color: rgb(38, 148, 255);">Remove this useless empty export.</span> <strong>1</strong> <strong>1</strong><strong> │ </strong> export const A = 0; <strong>2</strong> <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><strong>x</strong></span><span style="color: Tomato;"><strong>p</strong></span><span style="color: Tomato;"><strong>o</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: Tomato;"><strong>{</strong></span><span style="color: Tomato;"><strong>}</strong></span><span style="color: Tomato;"><strong>;</strong></span> <strong>3</strong> <strong>2</strong><strong> │ </strong> </code></pre>

Valid

jsx
export {};