How to make decisions based on whether an event reaches a node
Nodes that have an event door on an input port can let some events through and block others. If you want to do something different depending on whether the event was let through or blocked, you can use an Are All Hit node.
Below is an example that checks if a barcode was found in an image. Since the Find Barcode in Image node blocks events when no barcode is found, the Are All Hit node is used to check whether the event was blocked. Are All Hit outputs false if Find Barcode in Image blocks the event and true otherwise.