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# reactionEffectsInProgress

An array of reaction effects that the device is currently performing, sorted by timestamp.

```
var reactionEffectsInProgress: [AVCaptureReactionEffectState] { get }
```

## Discussion

Key-value observe this property to determine when reaction effects begin and end. If your key-value observing callback provides old and new values, any in-progress reaction effects in the new array have a value of <doc://com.apple.documentation/documentation/CoreMedia/CMTime/invalid> for their [`endTime`](/documentation/AVFoundation/AVCaptureReactionEffectState/endTime) property value. Completed reaction effects are only in the old array, and have their [`endTime`](/documentation/AVFoundation/AVCaptureReactionEffectState/endTime) property value set to the presentation time of the first frame where the reaction effect was no longer present.

---

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