1.基础(on)
// 如果像对象享有事件能力就要集成EventEmitter
const EventEmitter = require('events')
//集成EventEmitter类
class CustomEvent extends EventEmitter{
}
// 实例化对象
const ce = new CustomEvent()
//绑定一个事件名
ce.on('test',()=>{
console.log('this is a test');
})
setInterval(()=>{
ce.emit('test')
},500)运行效果就是不断的执行this is a test
2.传一些参数,基础信息
const EventEmitter = require('events')
class CustomEvent extends EventEmitter{}
const ce = new CustomEvent()
ce.on('error',(err,time)=>{
console.log(err);
console.log(time);
});
ce.emit('error',new Error('oops!'),Date.now())
3.执行一次就好了 once(下面即使是像之前on那样操作,也就是每个500毫秒执行一次,可是运行之后也就执行一次而已)
const EventEmitter = require('events')
class CustomEvent extends EventEmitter{}
const ce = new CustomEvent()
ce.once('test',()=>{
console.log('test event');
})
setInterval(()=>{
ce.emit('test')
},500)
4.移除工作,绑定了一些事件在某些场景下需要移除掉(removeListener 或者 removeAllListener)
const EventEmitter = require('events')
class CustomEvent extends EventEmitter{}
function fn1(){
console.log('fn1');
}
function fn2(){
console.log('fn2'); } const ce = new CustomEvent() ce.on('test',fn1) ce.on('test',fn2) setInterval(()=>{ ce.emit('test') },500) setTimeout(()=>{ // ce.removeListener('test',fn2) // ce.removeListener('test',fn1) //移除所有事件名的事件 ce.removeAllListeners('test') },1500)
