Vue Js EventBus

 // in some global file

const EventBus = new Vue();

// in GC1 (parent -> child 1 -> grand child 1)
EventBus.$emit('someEvent', 'some-data')

// in GC5 (parent -> child 3 -> grand child 5)
EventBus.$on('someEvent', function(data) {
  console.log(data) // 'some-data
})