Node.js: Range Query in MongoDB with multiple criteria, using Mongoose - mongodb

Question

I'm trying to implement a "range query" in MongoDB using Mongoose, ordered by a 'criteria' and then by '_id'.
And I would like to return to the client a string containing both cursors.
I was trying to implement something like the code below, with the commented block 2. However, I'm getting an error. Not even the log messages are being printed.
In my test, the query is empty, because the collection is empty.
I suspected that I was not getting the cursor, so I've tested with 'block 1' instead of block 2, and it worked.
But since I need the last cursor, I guess what I really need to use is the .toArray method, right?
What am I doing wrong?
Feed.find({
"criteria": {$lt: cursorCriteria},
"_id": {$lt: cursorId}
})
.sort({
criteria: -1,
_id: -1
})
.limit( 50 )
// block 1: just to test if I'm getting the cursor
.then( items => {
items.forEach( function(item) {
console.log('an item');
})
})
/* block 2: if I try this block instead of block 1, I get an error
.toArray( items => {
if (items.length > 0) {
console.log('not empty);
} else {
console.log('empty');
}
var nextCursor = '${item.criteria}_${item._id}';
res.status(200).json({item, nextCursor});
})
*/

Answer 1

Mongoose doesn't a have toArray() method
This worked fine:
.then( items => {
if (items.length > 0) {
console.log('not empty');
} else {
console.log('empty');
}
var nextCursor;
if (items.length > 0) {
nextCursor = '' + items[items.length-1].criteria + "_" + items[items.length-1]._id;
} else {
nextCursor = '';
}
res.status(200).json({items, nextCursor});
})