40行代码原生JS（ES6）事件总线实现

EventBus.js

export class BEvent {
  constructor (type, target, data) {
    this.type = type
    this.target = target
    this.data = data
  }
}

export class EventDispatcer {
  constructor () {
    if (window && window.EventBus) {
      throw new Error('这是一个单例！')
    }
    this.eventMap = new Map()
  }
  dispatchEvent (event) {
    let evtSet = this.eventMap.get(event.type)
    if (evtSet) {
      for (let item of evtSet.values()) {
        item(event)
      }
    }
  }
  addEventListener (eventType, func) {
    let evtSet = this.eventMap.get(eventType)
    if (!evtSet) {
      evtSet = new Set()
      this.eventMap.set(eventType, evtSet)
    }
    evtSet.add(func)
  }
  removeEventListener (eventType, func) {
    let evtSet = this.eventMap.get(eventType)
    if (evtSet) {
      evtSet.delete(func)
    }
  }
}
export default new EventDispatcer()

使用：

import EventBus from './EventBus'
//   定义事件监听器
EventBus.addEventListener('myevent',(evt)=>{
 console.log(evt)
})

const evt = new Event('myevent',this,{a:1})
EventBus. dispatchEvent(evt)