---
name: transformer-compile-class
description: Compile multiple classes into one hashed class
---
# Transformer Compile Class
Compiles multiple utility classes into a single hashed class for smaller HTML.
## Installation
```ts
import { defineConfig, transformerCompileClass } from 'unocss'
export default defineConfig({
transformers: [
transformerCompileClass(),
],
})
```
## Usage
Add `:uno:` prefix to mark classes for compilation:
```html
```
## Generated CSS
```css
.uno-qlmcrp {
text-align: center;
}
.uno-0qw2gr {
font-size: 0.875rem;
line-height: 1.25rem;
font-weight: 700;
}
.uno-0qw2gr:hover {
--un-text-opacity: 1;
color: rgb(248 113 113 / var(--un-text-opacity));
}
@media (min-width: 640px) {
.uno-qlmcrp {
text-align: left;
}
}
```
## Options
```ts
transformerCompileClass({
// Custom trigger string (default: ':uno:')
trigger: ':uno:',
// Custom class prefix (default: 'uno-')
classPrefix: 'uno-',
// Hash function for class names
hashFn: (str) => /* custom hash */,
// Keep original classes alongside compiled
keepOriginal: false,
})
```
## Use Cases
- **Smaller HTML** - Reduce repetitive class strings
- **Obfuscation** - Hide utility class names in production
- **Performance** - Fewer class attributes to parse
## ESLint Integration
Enforce compile class usage across project:
```json
{
"rules": {
"@unocss/enforce-class-compile": "warn"
}
}
```
This rule:
- Warns when class attribute doesn't start with `:uno:`
- Auto-fixes by adding the prefix
Options:
```json
{
"rules": {
"@unocss/enforce-class-compile": ["warn", {
"prefix": ":uno:",
"enableFix": true
}]
}
}
```
## Combining with Other Transformers
```ts
export default defineConfig({
transformers: [
transformerVariantGroup(), // Process variant groups first
transformerDirectives(), // Then directives
transformerCompileClass(), // Compile last
],
})
```