@nextcloud/event-bus

A simple event bus to communicate between Nextcloud components.

Installation

npm install @nextcloud/event-bus --save

yarn add @nextcloud/event-bus

Usage

import { emit, subscribe, unsubscribe } from '@nextcloud/event-bus'

const h = (e) => console.info(e)

subscribe('a', h)
subscribe('b', h)

emit('a', {
    data: 123,
})

unsubscribe('a', h)
unsubscribe('b', h)

It is also possible to type events, which allows type infering on the event-bus methods like emit, subscribe and unsubscribe. To register new events, simply extend the NextcloudEvents interface:

Create a file like event-bus.d.ts:

declare module '@nextcloud/event-bus' {
    interface NextcloudEvents {
        'example-app:awesomeness:increased': { level: number }
    }
}

export {}

Now if you use any of the event bus functions, the parameters will automatically be typed correctly:

import { subscribe } from '@nextcloud/event-bus'

subscribe('example-app:awesomeness:increased', (event) => {
    // "event" automatically infers type { level: number}
    console.log(event.level)
})