Document:
{ \"_id\" : ObjectId(\"560c24b853b558856ef193a3\"), \"name\" : \"Karl Morrison\", \"pic\" : \"\", \"language\" : ObjectId(\"560c24b
const ObjectId = mongoose.Types.ObjectId; const User = mongoose.model('User') User.aggregate([ { $match: { _id: ObjectId('560c24b853b558856ef193a3') } } ])