How to exit in Node.js




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What is the command that is used to exit? (i.e terminate the Node.js process)


Command Line

Press CTRL + C twice

OR

Type .exit and press enter

Script File

process.exit(code)

REPL(Command Line)

  • Press ctrl + c twice

  • Type .exit and press enter

Script File

process.exit(code)

Node normally exits with code 0 when no more async operations are pending.

process.exit(1) should be used to exit with a failure code.This will allow us to infer that node didn't close gracefully and was forced to close.

There are other exit codes like

3 - Internal JavaScript Parse Error ( very very rare)

5 - Fatal error in v8 javascript engine

9 - Invalid argument

For full list see node exit codes


Call the global process object's exit method:

process.exit()

From the docs:

process.exit([code])

Ends the process with the specified code. If omitted, exit uses the 'success' code 0.

To exit with a 'failure' code:

process.exit(1);

The shell that executed node should see the exit code as 1.


From code you can use process.exit([errorcode]) where [errorcode] is an optional integer (0 is the default to indicate success).

If you're using the Read Eval Print Loop (REPL), you can use Ctrl + D, or type .exit

Alternatively, on Windows or Linux you can use Ctrl + C, Ctrl + C

On Mac the command is Ctrl + Z, Ctrl + Z


From the official nodejs.org documentation:

process.exit(code)

Ends the process with the specified code. If omitted, exit uses the 'success' code 0.

To exit with a 'failure' code:

process.exit(1);

I have an application which I wanted to:

  1. Send an email to the user
  2. Exit with an error code

I had to hook process.exit(code) to an exit event handler, or else the mail will not be sent since calling process.exit(code) directly kills asynchronous events.

#!/usr/bin/nodejs
var mailer = require('nodemailer');
var transport = mailer.createTransport();
mail = {
  to: 'Dave Bowman',
  from: 'HAL 9000',
  subject: 'Sorry Dave',
  html: 'Im sorry, Dave. Im afraid I cant do <B>THAT</B>.'
}
transport.sendMail(mail);
//process.exit(1);
process.on('exit', function() { process.exit(1); });

If you're in a Unix terminal or Windows command line and want to exit the Node REPL, either...

  • Press Ctrl + C twice, or
  • type .exit and press Enter, or
  • press Ctrl + D at the start of a line (Unix only)

It depends on the reason why you're willing to exit node.js process, but in any case process.exit() is the last option to consider. A quote from documentation:

It is important to note that calling process.exit() will force the process to exit as quickly as possible even if there are still asynchronous operations pending that have not yet completed fully, including I/O operations to process.stdout and process.stderr.

In most situations, it is not actually necessary to call process.exit() explicitly. The Node.js process will exit on it's own if there is no additional work pending in the event loop. The process.exitCode property can be set to tell the process which exit code to use when the process exits gracefully.

Let’s cover possible reasons why you might be willing to exit node.js process and why you should avoid process.exit():

Case 1 - Execution complete (command line script)

If script has reached its end and node interpreter doesn't exit, it indicates that some async operations are still pending. It’s wrong to force process termination with process.exit() at this point. It’s better to try to understand what is holding your script from exiting in expected way. And when you settle this, you can use process.exitCode to return any result to calling process.

Case 2 - Termination because of external signal (SIGINT/SIGTERM/other)

For example, if you’re willing to gracefully shut down an express app. Unlike command line script, express app keeps running infinitely, waiting for new requests. process.exit() will be a bad option here because it’s going to interrupt all requests which are in pipeline. And some of them might be non-idempotent (UPDATE, DELETE). Client will never know if those requests are completed or not on server side and it might be the reason of data inconsistency between client and server. The only good solution is to tell http server to stop accepting new requests and wait for pending ones to finish with server.close():

var express = require('express');
var app = express();
var server = app.listen(80);

process.on( 'SIGTERM', function () {
   server.close(function () {
     console.log("Finished all requests");
   });
});

If it still doesn't exit - see Case 1.

Case 3 - Internal error

It's always better to throw an error, you’ll get a nicely formatted stack trace and error message. Upper levels of code can always decide if they can handle error (catch) or let it crash the process. On the other side, process.exit(1) will terminate process silently and there will be no chance to recover from this. It might be the only “benefit” of process.exit(), you can be sure that process will be terminated.


Press Ctrl + C twice or .exit.

> 
(To exit, press ^C again or type .exit)
> 

To exit

let exitCode = 1;
process.exit(exitCode)

Useful exit codes

1 - Catchall for general errors
2 - Misuse of shell builtins (according to Bash documentation)
126 - Command invoked cannot execute
127 - “command not found”
128 - Invalid argument to exit
128+n - Fatal error signal “n”
130 - Script terminated by Control-C
255\* - Exit status out of range

if you want to exit from node js application then write

process.exit(1)

in your code





node.js