event-bus.js

import Vue from 'vue'
export default new Vue()

NewPopover.vue

<script>
import EventBus from '@/services/event-bus'

export default {
  name: 'NewPopover',
  computed: {},
  watch: {
    showPopper (newVal, oldVal) {
      if (newVal) {
        this.disableBusListener()
        EventBus.$emit('close-all-popovers')
        setTimeout(this.enableBusListener, 10)
      } else {
        this.disableBusListener()
      }
    }
  },
  beforeDestroy () {
    this.disableBusListener()
  },
  methods: {
    disableBusListener () {
      EventBus.$off('close-all-popovers')
    },
    enableBusListener () {
      EventBus.$on('close-all-popovers', () => {
        console.log('got close-all-popovers event')
        this.showPopper = false
      })
    },
  }
}
</script>