#ctx.off()

Removes event listeners registered via ctx.on(eventName, handler). It is often used in conjunction with ctx.on to unsubscribe at the appropriate time, preventing memory leaks or duplicate triggers.

#Use Cases

#Type Definition

off(eventName: string, handler: (event?: any) => void): void;

#Examples

#Paired usage in React useEffect

React.useEffect(() => {
  const handler = (ev) => setValue(ev?.detail ?? '');
  ctx.on('js-field:value-change', handler);
  return () => ctx.off('js-field:value-change', handler);
}, []);

#Unsubscribing from resource events

const handler = () => { /* ... */ };
ctx.resource?.on('refresh', handler);
// At the appropriate time
ctx.resource?.off('refresh', handler);

#Notes

1. Consistent handler reference: The handler passed to ctx.off must be the same reference as the one used in ctx.on; otherwise, it cannot be correctly removed.
2. Timely cleanup: Call ctx.off before the component unmounts or the context is destroyed to avoid memory leaks.

#Related Documents

• ctx.on - Subscribe to events
• ctx.resource - Resource instance and its on/off methods