Cancel Element

The <cancel> element cancels a delayed event:

<cancel sendid="delayed-event" />

Examples

Basic Cancellation

<cancel sendid="reminder" />

Dynamic Cancellation

<cancel 
sendidexpr={({state}) => state.pendingEventId} 
/>

Multiple Event Cancellation

<state id="cleanup">
<onentry>
  <cancel sendid="reminder1" />
  <cancel sendid="reminder2" />
  <cancel sendid="reminder3" />
</onentry>
</state>

Usage Notes

• Use when you need to prevent a delayed event from occurring
• Commonly used in cleanup operations
• Useful for canceling timeouts and reminders
• Can be used with dynamic event IDs

Best Practices

1. Event Management

   • Keep track of event IDs systematically
   • Use meaningful event IDs
   • Clean up pending events when appropriate
   • Handle cases where the event might already be executed

2. Error Handling

   • Handle cases where the event ID doesn't exist
   • Provide appropriate feedback for cancellation failures
   • Log cancellation operations for debugging

3. State Coordination

   • Coordinate with send elements
   • Consider the timing of cancellations
   • Handle race conditions
   • Clean up related state data

4. Documentation

   • Document which events can be canceled
   • Explain cancellation conditions
   • Note any side effects
   • Include timing considerations