Home node.js: Async.parallel, callback is not a function
 So I want to get the amount of viewers from each subforum. I wanted to do this by using async.parallel and then receiving the results at the end. The problem is that I want to call the same function 4 times (one time for each subforum) with a different argument. How do I do this? The way you see it below is how I tried to do it, but it gave me an error that 'callback is not a function'. Does anyone know how to properly do this? Node.js code router.get('/getSubViews', function(req, res) { async.parallel([ getViewers('quests'), getViewers('tips & tricks'), getViewers('general'), getViewers('cities') ], function(err, result) { if (err) { return res.status(500).json({ message: "Something went wrong", err: err }); } res.status(200).json({ message: "Successfully retrieved the section", obj: 'whatever' }); }); function getViewers(subForum, callback){ SubViewCount.findOne({'section': subForum}, function(err, doc){ callback(null, doc.views); }) }