DatasyncEvent

The value of the node to which this event relates.

The returned value depends on eventType value:

• DatasyncEventType.valueChange or DatasyncEventType.valueAcknowledgement: The new value of the whole node (that is the node on which the subscription was taken).
• DatasyncEventType.childRemoval: The old value of the removed child.
• DatasyncEventType.childAddition, DatasyncEventType.childChange or DatasyncEventType.childAcknowledgement: The new value of the corresponding child. When the back-end acknowledges the removal of a child, this value is therefore null.

The key of the sibling child node that precedes the added or changed child in the visibility window.

The order of the keys is defined in the DatasyncChildrenConstraint documentation.

When the eventType is DatasyncEventType.childRemoval or DatasyncEventType.valueChange, this property is nil. When the added of changed child is the first one, this property is also nil.

The subscription that produces this event.

The atomic type of this event.

This property is useful when an event callback is used for a composite event type.

For example, if:

• DatasyncNode.subscribe(to:childrenConstraint:stores:file:line:queue:onEvent:onCompletion:) was called with eventType parameter having .child(addition: true, change: true, removal: false, acknowledgement: false) value (please note the true value for the addition associated value),
• and this event was triggered by a change in an already existing child,

then this value will be .child(addition: false, change: true, removal: false, acknowledgement: false) (please note the false value for the addition associated value this time), i.e. DatasyncEventType.childChange.

The key of the node to which this event relates.

The returned key depends on eventType value:

• DatasyncEventType.child(addition:change:removal:acknowledgement:): The key of the corresponding child.
• DatasyncEventType.value(change:acknowledgement:): The key of the node on which the subscription was taken.

A reference to the node to which this event relates.

The returned node reference depends on eventType value:

• DatasyncEventType.child(addition:change:removal:acknowledgement:): The corresponding child.
• DatasyncEventType.value(change:acknowledgement:): The node on which the subscription was taken.

When the manager of the node whose subscription has emitted this event no longer exists, this property is nil. This cannot happen when the subscription is stored by the manager, which corresponds to the default value of the stores parameter of the DatasyncNode.subscribe(to:childrenConstraint:stores:file:line:queue:onEvent:onCompletion:) method.