构造函数实现单例模式 观察者模式面试题

 请实现EventEmitter, 让打印输出符合预期
const eventBus = new EventEmitter()
const eventBus1 = new EventEmitter()
console.log(eventBus === eventBus1) // 打印输出: true
function handleClick(param1, param2) {
 console.log(param1, param2)
}
eventBus.on('click', handleClick)
eventBus.emit('click', 'foo', 'bar') // 打印输出: foo bar

function EventEmitterOrigin(){
    this.fn='';//用于存触发之后的事件
	this.name='click';
    this.emit=(name,...arg)=>{
	  if(name==this.name){
		  this.fn(...arg)//用于发布触发存储的fn
	  }
    }
    this.on=(name,fn)=>{
	   this.name=name;
		 this.fn=fn;//用于订阅存储下fn
		return this.fn
	 }
}
//单例模式只生成一个实例
let EventEmitter=(function(){
  let fac='';
  return function (){
    if(!fac){
      fac=new EventEmitterOrigin()
       return fac
     }
    return fac
   }
})()
// 请实现EventEmitter, 让打印输出符合预期
const eventBus = new EventEmitter()
const eventBus1 = new EventEmitter()
console.log(eventBus === eventBus1) // 打印输出: true
function handleClick(param1, param2) {
 console.log(param1, param2)
}
eventBus.on('click', handleClick)
eventBus.emit('click', 'foo', 'bar') // 打印输出: foo bar

标签：面试题,name,打印输出,EventEmitter,模式,eventBus,click,fn,构造函数
来源： https://blog.csdn.net/qq_34507902/article/details/122269990