If possible, do yourself a favor and test your code to make sure it works with NodeJS version 6.3 or greater.
Official support for Node.js debuggability landed in Node.js version 6.3 in May 2016.
Before v6.3: https://github.com/node-inspector/node-inspector
expose port 9229 if using docker
and start your code:
node --inspect --debug-brk myCode.js
it will output a url to connect with
chrome://inspect/#devices, go ahead and copy/paste that URL into chrome
sourcestab, place breakpoints where ever you want ... then hit play to let the code run
Your code starts in "paused" mode because of
take a snapshot, then:
either, run requests against web server to cause load
or, simply let your one-time nodejs code run until it hits a breakpoint
take another snapshot
compare heap snapshots in chrome devtools