Nodejs事件发射器程序中语句的执行顺序

Question

I tried the following NodeJs example:

const EventEmitter = require('events');
var eventEmitter = new EventEmitter();

var fun1 = (msg) => {
    console.log("Message from fun1: " + msg);
};
var fun2 = (msg) => {
    console.log("Message from fun2: " + msg);
};

eventEmitter.on('myEvent', fun1);
eventEmitter.on('myEvent', fun1);
eventEmitter.on('myEvent', fun2);

eventEmitter.removeListener('myEvent', fun1);
eventEmitter.emit('myEvent', "Event occurred");
console.log(eventEmitter.listenerCount('myEvent'));
eventEmitter.removeAllListeners('myEvent');
console.log(eventEmitter.listenerCount('myEvent'));

eventEmitter.emit('myEvent', "Event occurred");

Output is:

Message from fun1: Event occurred

Message from fun2: Event occurred

2

0

Please help me in understanding the output, as according to my expectation the line 'Message from fun2: Event occurred' shouldn't have been printed, as I've called removeAllListeners before it. And, Event emitter functions are called synchronously. Also, if Event emitter functions are really executed in synchronous manner, why are all the console logs getting printed at the very end?

Answer 1

Nodejs docs say

If any single listener has been added multiple times to the listener array for the specified eventName, then removeListener() must be called multiple times to remove each instance.

That's why it's still printing count as 2. Because there still are two listeners active for event "myevent" "fun1" and "fun2".