发布订阅模式classEventEmitter{constructor(){this.cache={}}//注册事件$on(eventType,fn){//添加事件this.cache[eventType]=this.缓存[事件类型]||[];this.cache[eventType].push(fn);}//注销事件$off(eventType){if(this.cache[eventType]){deletethis.cache[name];}}//触发事件$emit(eventType){if(this.cache[eventType]){this.cache[eventType].forEach(handle=>{handle();})}}}//测试让eventEmitter=newEventEmitter();functionf(){console.log("Jason");}eventEmitter.$on('click'f);eventEmitter.$emit('click');//JasoneventEmitter.$off('click');//点击事件注销eventEmitter.$emit('click');//点击事件不再存在
