I want to use Mongoose to return information about a user to populate their profile. I've been using findOne to populate a list of their comments along with basic profile information through embedded documents and with .populate. I want to get a count of the friends that they have by counting how many objects are in the friends array.
It looks like aggregate is one of doing that, but how can I use both? or is there a simple way of doing a count in the findOne query?
var UserSchema = new Schema({
username: String,
comments : [{ type: Schema.Types.ObjectId, ref: 'Comment' }],
friends: [
{
id: { type: Schema.Types.ObjectId, ref: 'User' },
permission: Number
}
]
})
var User = mongoose.model('User', UserSchema);
var Comment = mongoose.model('Comment', CommentSchema);
app.get('/profile/:username', function(req, res) {
User
.findOne({ username: req.params.username }, 'username friends -_id')
.populate({
path: 'current',
model: 'Comment',
select: 'comment author -_id date',
populate: {
path: 'author',
model: 'User',
select: 'username firstName lastName -_id'
}
})
.exec(function(err, user) {
//
})
)}If user returns with friends array, why don't you return just user.friends.length ?
If you want just count, use this
User.aggregate([
{
$match: { username: req.params.username }
},
{
$unwind: "$comments"
},
{
$lookup: {
from: "Comment",
localField: "comments",
foreignField: "_id",
as: "comments"
}
},
{
"$group": {
"_id": "$_id",
"friends": { "$first": "$friends"},
"comments": { "$push": "$comments" }
}
},
{
$project: {
_id: 0,
count: {$size: '$friends'},
comments: 1,
username: 1
}
}
]).exec() ...