Vue global bus as event hub

vue-event-hub.js

import Vue from "vue";

// Create the event bus by creating a new Vue instance and 
// binding it somehwere accessible. If you bind it to the
// Vue prototype, you can access it within your components
// like this:
//
// Emit an event
// this.$bus.$emit('myEvent', {data: true})
//
// React to an event
// this.$bus.$on('myEvent', (message) => {console.log(message})
Vue.prototype.$bus = new Vue({})

https://medium.com/patrickleenyc/vue-js-simple-event-bus-for-cross-component-communication-85dd8f0fc750
https://vuejs.org/v2/guide/migration.html#dispatch-and-broadcast-replaced