---
url: /reference/usignal.md
---

# @signaldb/usignal

## usignalReactivityAdapter (`default`)

```js
import { Collection } from '@signaldb/core'
import usignalReactivityAdapter from '@signaldb/usignal'
import { effect } from 'usignal'

const posts = new Collection({
  reactivity: usignalReactivityAdapter,
})

effect(() => {
  const cursor = posts.find({ author: 'John' })
  console.log(cursor.count())
  return () => {
    // usignal doesn't allow to do automatic cleanup, so we have to do it ourself
    cursor.cleanup()
  }
})
```

Reactivity adapter for usage with [µsignal](https://github.com/WebReflection/usignal).

The API of usignal doesn't allow [automatic cleanup](/reference/core/createreactivityadapter/#ondispose-callback-void-dependency-dependency-optional) nor [reactive scope checking](/reference/core/createreactivityadapter/#isinscope-dependency-dependency-boolean-optional).
With usignal, you can return a function from your `effect` that will be called on cleanup. Use this one to cleanup your cursors (see below for an example).
You also must manually disable reactivity when making calls outside a reactive scope to avoid memory leaks. You can do this by passing `{ reactive: false }` to your options (e.g. `<collection>.find({ ... }, { reactive: false })`).