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title: noEmptyInterface
description: Learn more about noEmptyInterface
---
import { Tabs, TabItem } from '@astrojs/starlight/components';

<Tabs>
<TabItem label="TypeScript and TSX" icon="seti:typescript">
## Summary
- Rule available since: `v1.0.0`
- Diagnostic Category: [`lint/suspicious/noEmptyInterface`](/reference/diagnostics#diagnostic-category)
- This rule is **recommended**, meaning it is enabled by default.
- This rule has a [**safe**](/linter/#safe-fixes) fix.
- The default severity of this rule is [**error**](/reference/diagnostics#error).
- Sources: 
  - Inspired from [`@typescript-eslint/no-empty-interface`](https://typescript-eslint.io/rules/no-empty-interface)

## How to configure
```json title="biome.json"
{
	"linter": {
		"rules": {
			"suspicious": {
				"noEmptyInterface": "error"
			}
		}
	}
}

```
## Description
Disallow the declaration of empty interfaces.

An empty interface in TypeScript does very little: any non-nullable value is assignable to `{}`.
Using an empty interface is often a sign of programmer error, such as misunderstanding the concept of `{}` or forgetting to fill in fields.

The rule ignores empty interfaces that `extends` one or multiple types.

## Examples

### Invalid

```ts
interface A {}
```

<pre class="language-text"><code class="language-text">code-block.ts:1:1 <a href="https://biomejs.dev/linter/rules/no-empty-interface">lint/suspicious/noEmptyInterface</a> <span style="color: #000; background-color: #ddd;"> FIXABLE </span> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━<br /><br />  <strong><span style="color: Tomato;">✖</span></strong> <span style="color: Tomato;">An </span><span style="color: Tomato;"><strong>empty interface</strong></span><span style="color: Tomato;"> is equivalent to </span><span style="color: Tomato;"><strong>&#123;&#125;</strong></span><span style="color: Tomato;">.</span><br />  <br />  <strong><span style="color: Tomato;">&gt;</span></strong> <strong>1 │ </strong>interface A &#123;&#125;<br />   <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><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><br />    <strong>2 │ </strong><br />  <br />  <strong><span style="color: lightgreen;">ℹ</span></strong> <span style="color: lightgreen;">Safe fix</span><span style="color: lightgreen;">: </span><span style="color: lightgreen;">Use a type alias instead.</span><br />  <br />    <strong>1</strong>  <strong> │ </strong><span style="color: Tomato;">-</span> <span style="color: Tomato;"><strong>i</strong></span><span style="color: Tomato;"><strong>n</strong></span><span style="color: Tomato;"><strong>t</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><strong>r</strong></span><span style="color: Tomato;"><strong>f</strong></span><span style="color: Tomato;"><strong>a</strong></span><span style="color: Tomato;"><strong>c</strong></span><span style="color: Tomato;"><strong>e</strong></span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">A</span><span style="color: Tomato;"><span style="opacity: 0.8;">·</span></span><span style="color: Tomato;">&#123;</span><span style="color: Tomato;">&#125;</span><br />      <strong>1</strong><strong> │ </strong><span style="color: MediumSeaGreen;">+</span> <span style="color: MediumSeaGreen;"><strong>t</strong></span><span style="color: MediumSeaGreen;"><strong>y</strong></span><span style="color: MediumSeaGreen;"><strong>p</strong></span><span style="color: MediumSeaGreen;"><strong>e</strong></span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;">A</span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;">·</span></span><span style="color: MediumSeaGreen;"><strong>=</strong></span><span style="color: MediumSeaGreen;"><span style="opacity: 0.8;"><strong>·</strong></span></span><span style="color: MediumSeaGreen;">&#123;</span><span style="color: MediumSeaGreen;">&#125;</span><br />    <strong>2</strong> <strong>2</strong><strong> │ </strong>  <br />  <br /></code></pre>

### Valid

```ts
interface A {
  prop: string;
}

// Allow empty interfaces that extend a type.
interface B extends A {}

// Allow empty interfaces in ambient modules
declare module "mod" {
  interface C {}
}
```

## Related links

- [Disable a rule](/linter/#disable-a-rule)
- [Configure the code fix](/linter#configure-the-code-fix)
- [Rule options](/linter/#rule-options)
- [Source Code](https://github.com/biomejs/biome/blob/main/crates/biome_js_analyze/src/lint/suspicious/no_empty_interface.rs)
- [Test Cases](https://github.com/biomejs/biome/blob/main/crates/biome_js_analyze/tests/specs/suspicious/noEmptyInterface)

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</Tabs>