passing an array to the .group function (nodejs and mongodb)

[Ramesh]

I am a newbie and learning, mongodb version 2.0.1, and nodejs
I learnt a lot by looking at the groups, but not many posts
about .group() aggregate function.

I have a main collection releases with a mill rows:
{
"_id" : ObjectId("4f8795337eff37dfe18510dd"),
"chmid" : 555,
"other" : 0
}

Another chems
{
"_id" : ObjectId("4f888870a75a4247f0e79205"),
"chmid" : 555,
"chmname" : "METHANOL"
}

I group on the releases, and try to retrieve the chmname from a cached
array.
in node.js I have this code:

releases.group(
{ chmid: true },
{ y: 1},
{ total_count: 0, row_ctr: 0, cmps: [], lkp:
this.cachedChemNames },
function (doc, out) {
out.total_count += doc.Total;
var chmidx = doc.chmid - 1; <-- index
matches chmid
out.chmname = lkp[chmidx]; <---
db.findOne() takes a longer time, hence using a cached array
out.row_ctr++;
},
function (out) { },
function(err,doc){});

Any help greatly appreciated! Thanks.

[Mike O'Brien]

Hi Ramesh,

What's the issue you're having with this code? Is it returning an
error message?

-Mike

[Ramesh]

No error message is returned. I don't see any results.
I see the results if the offending line is removed. I see results if
findOne() is used.
Is there a way to debug that procedure ? console.log or sys.put dont
show any output either.

[Mike O'Brien]

Ramesh,
Are there any error messages being printed to the server logs? I'm
getting "JS Error: ReferenceError: lkp is not defined"
I think you need to reference it as "out.lkp"
You can use print("message") for debugging, these messages will get
printed to the server logs as well.