Node.js事件

const EventEmitter = require('events');

class MyEmitter extends EventEmitter {}
const myev = new MyEmitter();
myev.on('event',function(a,b){
    console.log(a,b,this);
})

myev.emit('event',"hello","world");
const myEmitter = new MyEmitter();
myEmitter.on('event', (a, b) => {
  setImmediate(() => {
    console.log(a+b+'这个是异步发生的');
  });
});
myEmitter.emit('event', 'a', 'b');