Events

Define event names with their payload types:

public static class AppEvents
{
    public static readonly CarbonEventName<int> CountChanged = new("count:changed");
}

Emit to every listener, only the C# application, or one labeled window:

await app.EmitAsync(AppEvents.CountChanged, 4);
await app.EmitAsync(
    AppEvents.CountChanged,
    5,
    CarbonEventTarget.Window("settings"));

Listen repeatedly or once. Dispose the returned subscription to unlisten.

using var subscription = app.Events.Listen(
    AppEvents.CountChanged,
    evt => Console.WriteLine(evt.Payload));

app.Events.Once(AppEvents.CountChanged, evt => Save(evt.Payload));

For trimmed or NativeAOT applications, use overloads that accept JsonTypeInfo<T> from a generated JsonSerializerContext.

Frontend events

Augment the event map when defining application events:

declare module '@dotcarbon/api' {
  interface CarbonEvents {
    'count:changed': number
  }
}

import { emit, listen, once } from '@dotcarbon/api'

const stop = await listen('count:changed', event => {
  console.log(event.payload, event.source)
})

await emit('count:changed', 6)
await emit('count:changed', 7, {
  target: { kind: 'window', label: 'settings' },
})

await once('count:changed', event => console.log(event.payload))
stop()

Frontend emission requires the core:event_emit capability.