Global Event Bus     

// outside of a Vue component:
import { Events } from 'quasar'
Events.$on('app:visibility', state => {
  console.log('App became', state)
})

// inside a Vue component:
this.$q.events.$on('app:visibility', state => {
  console.log('App became', state)
})
// in this case, make sure you unregister your handler
// when the Vue component gets destroyed

// on a Vue component:
export default {
  ...,
  created () {
    this.handler = state => {
      console.log('App became', state)
    }
    this.$q.events.$on('app:visibility', this.handler)
  },
  beforeDestroy () {
    this.$q.events.$off('app:visibility', this.handler)
  }
}

import { Events } from 'quasar'

Events.$on('some-event', (param1, param2) => {
  //...
})

import { Events } from 'quasar'

// Unregistering an event:
Events.$off('event-name')
// 'event-name' does no longer has any callbacks

// Unregistering a specific callback for an event:
let callback = function(...) {...}
Events.$on('event-name', callback)
Events.$off('event-name', callback)
// 'event-name' still exists (if other callbacks are registered to this event),
// but does not contain the above callback anymore

import { Events } from 'quasar'

let callback = function(...) {...}
Events.$once('event-name', callback)
// callback will be triggered only once

import { Events } from 'quasar'

Events.$emit('event-name')
// All callbacks associated with 'event-name' will be triggered
// in the order that they were registered.

// Trigger with parameters (as many as you want):
Events.$emit('event-name', {
  status: 10,
  message: 'wow',
  obj: true
})
// The parameters will be used when calling all registered
// callbacks for 'event-name' --> callback({status: 10, message: 'wow',...});