* `code` {Integer} The exit code. Defaults to `0`.

The `process.exit()` method instructs Node.js to terminate the process as

quickly as possible with the specified exit `code`. If the `code` is omitted,

exit uses either the 'success' code `0` or the value of `process.exitCode` if

specified.

The shell that executed Node.js should see the exit code as `1`.

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.

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:

if (someConditionNotMet()) {

printUsageToStdout();

process.exit(1);

}

The reason this is problematic is because writes to `process.stdout` in Node.js

are *non-blocking* 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:

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()`.

Specifying a code to [`process.exit(code)`][`process.exit()`] will override any

previous setting of `process.exitCode`.