exit
The process.exit()
method instructs Node.js to terminate the process synchronously with an exit status of code
. If code
is omitted, exit uses either the 'success' code 0
or the value of process.exitCode
if it has been set. Node.js will not terminate until all the 'exit'
event listeners are called.
To exit with a 'failure' code:
import { exit } from 'node:process';
exit(1);
The shell that executed Node.js should see the exit code as 1
.
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 its 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.
For instance, the following example illustrates a misuse of the process.exit()
method that could lead to data printed to stdout being truncated and lost:
import { exit } from 'node:process';
// This is an example of what *not* to do:
if (someConditionNotMet()) {
printUsageToStdout();
exit(1);
}
The reason this is problematic is because writes to process.stdout
in Node.js are sometimes asynchronous and may occur over multiple ticks of the Node.js event loop. Calling process.exit()
, however, forces the process to exit before those additional writes to stdout
can be performed.
Rather than calling process.exit()
directly, the code should set the process.exitCode
and allow the process to exit naturally by avoiding scheduling any additional work for the event loop:
import process from 'node:process';
// How to properly set the exit code while letting
// the process exit gracefully.
if (someConditionNotMet()) {
printUsageToStdout();
process.exitCode = 1;
}
If it is necessary to terminate the Node.js process due to an error condition, throwing an uncaught error and allowing the process to terminate accordingly is safer than calling process.exit()
.
In Worker
threads, this function stops the current thread rather than the current process.
Since
v0.1.13
Parameters
code=0 The exit code. For string type, only integer strings (e.g.,'1') are allowed.