why-is-node-running
Node.js is running but you don't know why? why-is-node-running is here to help you.
Installation
If you want to use why-is-node-running in your code, you can install it as a local dependency of your project. If you want to use it as a CLI, you can install it globally, or use npx to run it without installing it.
As a local dependency
Node.js 20.11 and above (ECMAScript modules):
Node.js 8 or higher (CommonJS):
As a global package
why-is-node-running /path/to/some/file.js
Alternatively if you do not want to install the package globally, you can run it with npx:
Usage (as a dependency)
import { createServer } from 'node:net'
function startServer () {
const server = createServer()
setInterval(() => {}, 1000)
server.listen(0)
}
startServer()
startServer()
// logs out active handles that are keeping node running
setImmediate(() => whyIsNodeRunning())
Save the file as example.js, then execute:
Here's the output:
There are 4 handle(s) keeping the process running
# Timeout
example.js:6 - setInterval(() => {}, 1000)
example.js:10 - startServer()
# TCPSERVERWRAP
example.js:7 - server.listen(0)
example.js:10 - startServer()
# Timeout
example.js:6 - setInterval(() => {}, 1000)
example.js:11 - startServer()
# TCPSERVERWRAP
example.js:7 - server.listen(0)
example.js:11 - startServer()
Usage (as a CLI)
You can run why-is-node-running as a standalone if you don't want to include it inside your code. Sending SIGUSR1/SIGINFO signal to the process will produce the log. (Ctrl + T on macOS and BSD systems)
probing module /path/to/some/file.js
kill -SIGUSR1 31115 for logging
To trigger the log:
kill -SIGUSR1 31115
Usage (with Node.js' --import option)
You can also use Node's --import option to preload why-is-node-running:
The steps are otherwise the same as the above CLI section
License
MIT