Performing Operations while Closing NodeJS - node.js

Question

I have a Firebase Connection in nodejs that pushes data to a url while the connection is persistent, when it closes, I want to remove that data (think, I push "hey I'm here", and when I leave, the text disappears)
I made a "runnable" that shows an example of it:
http://web-f6176e84-c073-416f-93af-62a9a9fbfabd.runnable.com
basically, hit "ctrl + c" and it prints out "trying to remove reference" but never actually deletes the data ( the documents say that remove() is equivalent to set(null) which it basically sets the data to null, and since it's null, the entire element should be gone.)
However it's not removing it, I don't see the data ever "disappear". (I'm using a temp Firebase URL, you should be able to duplicate with any URL you can access if this url stops existing).
this is the code I'm using.
var FB_URL = 'https://cuhiqgro1t3.firebaseio-demo.com/test_code';
var Firebase = require('firebase');
var myRootRef = new Firebase(FB_URL);
console.log("created Firebase URL");
process.stdin.resume(); //so the program will not close instantly
function delete_fb_entries() {
return function() {
console.log("Trying to remove reference");
myRootRef.remove();
process.exit();
}
}
//do something when app is closing
process.on('exit', delete_fb_entries());
//catches ctrl+c event
process.on('SIGINT', delete_fb_entries());
//catches uncaught exceptions
process.on('uncaughtException', delete_fb_entries());
EDIT: Additional Information as to the "why", I push my local IP address out to my Firebase URL cause I'm lazy and it's easier to just have a webpage setup I can always access that will show the url of particular devices (and I know using the routers tables would be easier), I actually also have other purposes for this usage as well (if I happen to be inside my network, I can just select a particular device from my webpage and access the data I need, either way, it works, but I just can't get it to remove itself correctly, this used to work at one point in time I believe, so I can only assume the API has changed or something).
EDIT 2: OK removed process.exit() as suggested, and the runnable seemed to delete the data in question, I tried it on my local data (and after some cleaning up and commenting out), it removed the data, however when I hit Ctrl + C it no longer exits the program.....so yay.
I need to figure out if "process.exit()" is necessary or unnecessary at this point.
Edit 3: Ok so I need to use process.exit (as far as I can tell, Ctrl + C no longer exits the program, I have to ctrl + Z, and reboot). I tried adding it right after, but I realized that removing a firebase element is not a synchronus operation, so when I close it I tried (the next attempt) was to use the on complete handler for the remove function (so remove(onComplete), and then adding the process.exit() to the onComplete function).
So finally it looks like this and it seems to be working with my application
var FB_URL = 'https://cuhiqgro1t3.firebaseio-demo.com/test_code';
var Firebase = require('firebase');
var myRootRef = new Firebase(FB_URL);
console.log("created Firebase URL");
function onComplete() {
process.exit();
]
process.stdin.resume(); //so the program will not close instantly
function delete_fb_entries() {
return function() {
console.log("Trying to remove reference");
myRootRef.remove(onComplete);
}
}
//do something when app is closing
process.on('exit', delete_fb_entries());
//catches ctrl+c event
process.on('SIGINT', delete_fb_entries());
//catches uncaught exceptions
process.on('uncaughtException', delete_fb_entries());
EDIT 4: In response to comments below, So I tried modifying a simple program to be the following:
function delete_fb_entries (){
return function () {
console.log("I should quit soon");
}
}
process.stdin.resume(); //so the program will not close instantly
//catches ctrl+c event
process.on('SIGINT', delete_fb_entries());
My program never exited. I don't understand why node would not close in this case, changing to add a process.exit() after the console.log causes nodejs to quit. This is not an async function, so why is it not exiting in this case? (Is this a bug, or a misunderstanding of how this works by me?)

Answer 1

You cannot perform asynchronous operations in a process's exit event handler, only synchronous operations, since the process is exited once all exit event handlers have been executed.