# How to exit in Node.js

Exiting a Node.js application is simple and can be done using the `process.exit()` method. This method exits from the current Node.js process and takes an exit code, which is an integer. The exit code can be either 0 or 1. 0 means end the process without any kind of failure and 1 means end the process with some failure.

Here’s how you can use the `process.exit()` method:

```jsx
if (someConditionNotMet()) {
  console.log('Usage: node <filename>');
  process.exit(1);
}
```

In the above example, if `someConditionNotMet()` returns `true`, the message `Usage: node <filename>` is printed to the console and the process exits with an exit code of 1.

It’s 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 its own if there is no additional work pending in the event loop.

Here are some other ways to exit a Node.js application:

1. **Throwing an Error**: You can throw an error to exit a Node.js application. This method is useful when you want to exit the application with a specific error message.

```jsx
throw new Error('Something went wrong');
```

2. **Using the `process.kill()` Method**: You can use the `process.kill()` method to terminate a Node.js process. This method sends a signal to the process to terminate it. The signal can be either `SIGTERM` or `SIGKILL`.

```jsx
process.kill(process.pid, 'SIGTERM');
```