using db.mycollection.distinct('field1', 'field2') with mongodb / mongoskin - node.js

Question

I have the following line in an exports declaration in a user.js file:
db.collection('myList').distinct('field1', 'field2'), function(err, items) {
res.json(items);
}
The db lookup works fine from the mongo command line. However, when I run the webpage, I get:
TypeError: string is not a function
I'm not certain how to proceed at this point. Should I be casting the return to a string somehow before returning it?
Thanks.

Answer 1

Your question does not seem to be well defined, consider the logic:
> db.info.insert({ field1: "this", field2: "that" })
> db.info.insert({ field1: "this", field2: "another" })
> db.info.insert({ field1: "this", field2: "that" })
> db.info.insert({ field1: "this", field2: "another" })
> db.info.distinct('field1', 'field2')
[ "this" ]
But what you actually want is:
db.info.aggregate([
{$group: {_id: { field1: "$field1", field2: "$field2" } } }
])
Which gives:
{
"result" : [
{
"_id" : {
"field1" : "this",
"field2" : "another"
}
},
{
"_id" : {
"field1" : "this",
"field2" : "that"
}
}
],
"ok" : 1
}
The distinct results of the combined fields.
I hope we are learning now.

Answer 2

For some odd reason MongoSkin abstraction doesn't provide access to the MongoDB 'distinct' method. To get distinct to work, I had to use the native MongoDB collection and not the abstracted MongoSkin collection. Here is how I did it
var store = mongo.db(connectionString, ackOptions);
store.open(function(err,resp){
resp.collection(this.options.collection, {strict: true}, function(err, myCollection) {
myCollection.distinct('tag',function(err,res){
console.log(err)
console.log(res)
})
});
})