Lume.js
Reactivity that follows web standards.
Minimal reactive state management using only standard JavaScript and HTML.
No custom syntax · No build step · No framework lock-in.
1.49 KB universal core · 2.77 KB with DOM
npm install lume-js
Docs & live examples →
---
## Why Lume.js?
| Feature | Lume.js | Alpine.js | Vue | React |
|---------|---------|-----------|-----|-------|
| Custom Syntax | ❌ No | ✅ `x-data` | ✅ `v-bind` | ✅ JSX |
| Build Step | ❌ Optional | ❌ Optional | ⚠️ Recommended | ✅ Required |
| Bundle Size | 1.49–2.77KB | ~15KB | ~35KB | ~45KB |
| HTML Validation | ✅ Pass | ⚠️ Warnings | ⚠️ Warnings | ❌ JSX |
| Extensible Handlers | ✅ | ❌ Built-in only | ❌ Built-in only | N/A |
**Lume.js is "Modern Knockout.js" — standards-only reactivity for the modern web.**
---
## Installation
### Pick your entry
| Entry | Size (gz) | Contents | For |
|-------|-----------|----------|-----|
| `lume-js/state` | **1.49 KB** | `state`, `batch`, `withReadObserver` | Node, Deno, Bun, workers, CLI — anywhere without a DOM |
| `lume-js` | **2.77 KB** | + `bindDom`, `effect` | Browsers |
| `lume-js/addons` | pay per import | `computed`, `watch`, `repeat`, `persist`, … | Optional patterns |
| `lume-js/handlers` | pay per import | `show`, `classToggle`, `on`, … | Extra reactive attributes |
### Via CDN (Recommended for simple projects)
```html
```
DOM-free kernel only (servers, workers, embedded):
```html
```
### Via NPM (Recommended for bundlers)
```bash
npm install lume-js
```
```javascript
import { state, bindDom } from 'lume-js'; // browser: full core
import { state, batch } from 'lume-js/state'; // Node/CLI/workers: 1.49 KB kernel
```
> **→ Using Lume without a DOM?** See the [Universal core guide](docs/guides/universal-core.md).
### Browser Support
| Browser | Minimum version |
|---------|-----------------|
| Chrome | 80+ |
| Firefox | 74+ |
| Safari | 13.1+ |
| Edge | 80+ |
| IE11 | ❌ Not supported |
The floor comes from optional chaining / nullish coalescing (ES2020) used in the source — shipped un-transpiled, true to no-build. IE11 cannot be polyfilled regardless: Lume uses `Proxy`.
---
## Quick Start
**HTML:**
```html