why this code is only printing the first statement as output-CodePudding

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

var fn1 = function() {
  console.log("first fn executed on triggering first event  ")
  eventEmitter.emit('fn1')
}
eventEmitter.on("event1", fn1)
eventEmitter.emit('event1')
eventEmitter.on('fn1', function() {
  console.log("This is the fn triggered on 2nd event")
})

output on executing it by node event1.js is " first fn executed on triggering first event "

CodePudding user response：

Because the handler is registered after the event is fired. Try this:

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

var fn1 = function() {
    console.log("first fn executed on triggering first event  ")
    eventEmitter.emit('fn1')
}
eventEmitter.on("event1", fn1)

eventEmitter.on('fn1', function() {
    console.log("This is the fn triggered on 2nd event")
})
eventEmitter.emit('event1')