08慕课网《进击Node.js基础（一）》事件events

var EventEmitter = require(‘events‘).EventEmitter

var life = new EventEmitter()
//加不加都没有报警告
//life.setMaxListeners(10)

life.on(‘clickEvent‘,function(who){
    console.log(‘给‘ + who + ‘ 倒水‘)
})

life.emit(‘clickEvent‘,‘汉子1‘)

var hasClickListener = life.emit(‘clickEvent‘,‘汉子12‘)
var hasChangeListener = life.emit(‘changeEvent‘,‘妹子1‘)

 console.log(hasClickListener)
 console.log(hasChangeListener)
 console.log(hasPutListener)

//可以放到 on 和 emit 后面
function water(who){
    console.log(‘给 ‘ + who + ‘ 倒水‘)
}

life.on(‘changeEvent‘,water)
//还没有被取消，emit不能放到 on之前
life.emit(‘changeEvent‘,‘张三‘)
//water不可以用匿名函数，removeListener需要在emit之前
life.removeListener(‘changeEvent‘,water)
//移除所有监听，可以传递事件名作为参数
//life.removeAllListeners()


var hasChangeListener = life.emit(‘changeEvent‘,‘妹子1‘)//监听被取消
var hasPutListener = life.emit(‘clickEvent‘,‘李白‘)
// //是否被监听
 console.log(hasChangeListener)
 console.log(hasPutListener)

console.log(‘changeEvent：‘ + life.listeners(‘changeEvent‘).length)
console.log(‘clickEvent：‘ + life.listeners(‘clickEvent‘).length)
console.log(‘all：‘ + life.listeners.length)
//EventEmitter提供的方法
console.log(‘EventEmitter提供：‘)
console.log(‘changeEvent:‘ + EventEmitter.listenerCount(life,‘changeEvent‘))
console.log(‘clickEvent:‘ + EventEmitter.listenerCount(life,‘clickEvent‘))