> ## Documentation Index
> Fetch the complete documentation index at: https://docs.trysignal.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Super properties

> Register properties included with every event using register, registerOnce, and unregister

# Vue / Browser — Super properties

Super properties are automatically included with every event you capture. Use `register()` to add properties, `registerOnce()` to add them only if not already set, and `unregister()` to remove them.

## register(properties)

Add properties that will be included with every event. Overwrites existing properties with the same keys.

| Parameter    | Type                      | Required | Description                           |
| ------------ | ------------------------- | -------- | ------------------------------------- |
| `properties` | `Record<string, unknown>` | yes      | Properties to include with all events |

**When to use:** Properties that apply to all events (e.g. app version, environment, user role, A/B test variants).

## registerOnce(properties)

Add properties only if they are not already registered. Useful for one-time attributes.

| Parameter    | Type                      | Required | Description                                      |
| ------------ | ------------------------- | -------- | ------------------------------------------------ |
| `properties` | `Record<string, unknown>` | yes      | Properties to register (only if not already set) |

**When to use:** Properties that should be set once and never overwritten (e.g. initial app version, first session date).

## unregister(propertyName)

Remove a super property so it's no longer included with events.

| Parameter      | Type     | Required | Description                    |
| -------------- | -------- | -------- | ------------------------------ |
| `propertyName` | `string` | yes      | Name of the property to remove |

**When to use:** When a property no longer applies (e.g. user leaves an A/B test, app version is deprecated).

## getSuperProperties()

Get all currently registered super properties. Returns `Record<string, unknown>`.

**When to use:** Debugging or checking which properties are registered.

## Vue example

```vue theme={null}
<script setup>
import { onMounted, onUnmounted } from 'vue'
import { createSignal } from '@signal-js/browser'

let signal = null

onMounted(async () => {
  signal = createSignal({ endpoint: '...', apiKey: '...', projectId: '...' })
  await signal.start()
  
  // Register app version with all events
  signal.register({ appVersion: '1.2.3', environment: 'production' })
  
  // Register environment only once
  signal.registerOnce({ initialAppVersion: '1.0.0' })
})

onUnmounted(() => {
  // Clean up when component unmounts
  signal?.unregister('appVersion')
})
</script>
```

## Vanilla JS example

```javascript theme={null}
const signal = createSignal({ endpoint: '...', apiKey: '...', projectId: '...' });
await signal.start();

// Register app version - will be included in all events
signal.register({ appVersion: '1.2.3', environment: 'production' });

// Register initial app version only once
signal.registerOnce({ initialAppVersion: '1.0.0' });

// Later, update app version (overwrites previous value)
signal.register({ appVersion: '1.2.4' });

// Get all super properties
const superProps = signal.getSuperProperties();
console.log('Super properties:', superProps);

// Remove app version
signal.unregister('appVersion');
```

## Example: A/B testing

```javascript theme={null}
// Register experiment variant
signal.register({ experimentVariant: 'variant_a' });

// All events will include experimentVariant: 'variant_a'
signal.capture('button_clicked', { buttonId: 'cta' });

// Later, remove experiment variant
signal.unregister('experimentVariant');
```

## See also

* [Capture](/docs/integrations/vue/capture) — Track events (super properties are included automatically)
* [Identify](/docs/integrations/vue/identify) — Set user identity