---
title: "JavaScript Reactive Lamp Example with LemonadeJS v4"
description: "LemonadeJS v4 archive. How to create a simple state change using LemonadeJS version 4."
source: https://lemonadejs.com/docs/v4/examples/lamp/
---
Lamp
====
A LemonadeJS `self` property value will be synchronized with the HTML attribute.
A working example
-----------------
### Source code
```html
```
```javascript
import lemonade from 'lemonadejs';
export default function Lamp() {
const self = this;
self.on = () => {
self.state = 1;
}
self.off = () => {
self.state = 0;
}
return ``;
}
```
[See this example on codesandbox](https://codesandbox.io/s/reactive-javascript-library-83xmr7)