How can I get a list of callbacks in the Node work queue? (or, Why won't Node exit?)
node.jsnode.js Problem Overview
It says on the Node.js about page:
> Node exits the event loop when there are no more callbacks to perform.
Is there a way to find out which callbacks are keeping Node from exiting?
node.js Solutions
Solution 1 - node.js
You can use process._getActiveHandles() and process._getActiveRequests()
See this discussion in node.js mailing list.
update: there is a good package for this - https://github.com/mafintosh/why-is-node-running
Solution 2 - node.js
There is a npm module wtfnode to show what keep the nodejs app running when you sends SIGINT (ctrl-c) to it.
It internal uses process._getActiveHandles() as mentioned in @andrey-sidrov's answer. The benefit of using wtfnode is that it provides easy-to-read output.
Solution 3 - node.js
If you are interested to find out which open connections are still open:
While the process hangs, you can run in mac and linux: netstat -a to search for open ports. It's a good clue that helps me from time to time when it comes to why Jest is hanged.