I'm in the middle of looking for some memory leaks at the moment, in order to isolate them I wanted to confirm exactly how much memory was being used by a given line of code after garbage collection.
Fortunately V8 allows you to manually force garbage collection from within Javascript.
When you run your node script just add the option: '--expose-gc'
e.g:
node --expose-gc test.js
And then from within the Javascript just do:
global.gc();
That's it, good luck finding those leaks!