Smallest vm by datastore

I'm trying to find a way to output the smallest vm inside a datastore input. When you use vm.summary.storage.committed you can be looking at several vmdks that span multiple datastores.

I have this but I get an undefined return on the output for line#24.

The output on line#15 doesn't just show me a single devices, looks like it's the entire list of devices for the first VM of datastoreVmList

function sortDisk (a, b)
{
return (a.deviceInfo.summary - b.deviceInfo.summary);
}
System.log("First vm is " + datastoreVmList[0]);
System.log("Datastore is " + datastore);
var allDevices = new Array();
for (var i in datastoreVmList) {  var devices = datastoreVmList[i].config.hardware.device  allDevices.push(devices)
}
System.log("First device on array of devices is " + allDevices[0]);
var datastoreDisks = new Array();
for (var i in allDevices) {  if (allDevices[i] instanceof VcVirtualDisk == datastore) {  datastoreDisks.push(allDevices[i])  }
}
System.log("First disk device is " + datastoreDisks[0]);
datastoreDisks.sort(sortDisk);
datastoreDisks.reverse;
smallestVm = datastoreDisks[0].parent;
System.log("First disk device datastore is " + datastoreDisks[0].backing.datastore);
System.log("Smallest VM is " + smallestVm);

What would be the best way to do this?

Thanks!