bus.js

import Vue from 'vue';

class EventBus {
  constructor(vue) {
    if (!this.handles) {
      Object.defineProperty(this, 'handles', {
        value: {},
        enumerable: false,
      });
    }
    this.Vue = vue;
    this.eventMapUid = {};
  }

  setEventMapUid(uid, eventName) {
    if (!this.eventMapUid[uid]) this.eventMapUid[uid] = [];
    this.eventMapUid[uid].push(eventName);
  }

  $on(eventName, callback, vm) {
    if (!this.handles[eventName]) this.handles[eventName] = [];
    this.handles[eventName].push(callback);
    if (vm instanceof this.Vue) this.setEventMapUid(vm._uid, eventName); // eslint-disable-line
  }

  $emit() {
    const args = [...arguments]; // eslint-disable-line
    const eventName = args[0];
    const params = args.slice(1);
    if (this.handles[eventName]) {
      const len = this.handles[eventName].length;
      for (let i = 0; i < len; i++) { // eslint-disable-line
        this.handles[eventName][i](...params);
      }
    }
  }

  $offVmEvent(uid) {
    const currentEvents = this.eventMapUid[uid] || [];
    currentEvents.forEach((event) => {
      this.$off(event);
    });
  }

  $off(eventName) {
    delete this.handles[eventName];
  }
}

const $EventBus = {};
/* eslint-disable */
$EventBus.install = Vue => {
  window.$eventBus = new EventBus(Vue);
  Vue.prototype.$eventBus = new EventBus(Vue);
  Vue.mixin({
    beforeDestroy() {
      this.$eventBus.$offVmEvent(this._uid); // eslint-disable-line
    },
  });
};

Vue.use($EventBus);