useOpenerEventChannel()

A composable for the opened page to obtain the directed communication channel with its opener — the opened-side composable entry point of the EventsPlugin EventChannel semantics.

import { useOpenerEventChannel } from '@meng-xi/unix-router'

Signature

function useOpenerEventChannel(): EventChannel | null

Preconditions (returns null without throwing when any of them is unmet):

• The router has registered EventsPlugin;
• The current page was opened by a navigation carrying events (the page URL query contains the plugin-injected __evt__ channel key).

The Returned EventChannel

Member	Description
emit(eventName, ...args)	Sends data back to the opener (triggers the listener of the same name registered in the opener's events)
on(eventName, handler)	Listens for data pushed by the opener
once(eventName, handler)	Same as on, but auto-removed after firing once
off(eventName, handler?)	Removes a listener

Example

// Opener: register listeners via events
router.push({
	name: 'detail',
	events: {
		saved: (data) => {
			console.log('detail page saved', data)
		}
	}
})

// Opened page: get the channel and send data back to the opener
const channel = useOpenerEventChannel()
if (channel !== null) {
	channel.emit('saved', { id: 1024 })
}

Timing

The channel key prefers the in-memory value written during route sync; when the page's onShow runs before route sync (onRouteSync), it falls back to reading the __evt__ param of the current page URL. When neither is available it returns null — check for null at the call site.

Related APIs

• EventsPlugin — the full page-communication guide (events registry / eventBus / EventChannel)
• useRouter() — the opener registers listeners via push({ events })