nodejs学习：6基础API（四）events--2

1、如何传给事件处理程序一些信息：

const EventEmitter = require('events')

class CustomEventEmitte extends EventEmitter {

}

const ce = new CustomEventEmitte()

ce.on('error', (err,time) => {
  console.log(err)
  console.log(time)
})

ce.emit('error', new Error('opps!'), Date.now())

2、如果事件只想触发一次:once

ce.once('error', (err,time) => {

3、移除一个或全部：

function fn1 () {
  console.log('fn1')
}
function fn2 () {
  console.log('fn2')
}
ce.on('test', fn1);
ce.on('test', fn2);

setInterval(() => { 
  ce.emit('test')
},500)

setTimeout(() => { 
  ce.removeListener('test', fn1)
},1500)

setTimeout(() => { 
  ce.removeAllListener('test', fn1)
},5000)