I want to get data from my database to work with variables.
Here is my database query:
db.progress.find({username:socket},function(err,res){
what do I get information on:
[ { _id: 61e180b54e0eea1454f8e5e6,
username: 'user',
exp: 0,
fraction: 'undf'} ]
if i send a request
db.progress.find({username:socket},{exp:1},function(err,res){
then in return I will get
[ { _id: 61e180b54e0eea1454f8e5e6, exp: 0 } ]
how do i extract only 0 from the received data. I would like to do something like this.
var findprogress = function(socket,cb){
db.progress.find({username:socket},function(err,res){
cb(res.exp,res.fraction)
})
}
findprogress(socket,function(cb){
console.log(cb.exp)//0
console.log(cb.fraction)//undf
})
but I don't know how to implement it correctly.
I recommend aggregate in this case so you can more easily manipulate your projected data. For example:
db.progress.aggregate([
{ $match: { username: socket } },
{ $project: { _id: 0, exp: 1 } }
])
This way you directly tell the query to not include the objectId, which is typically included by default.
Try to give 0 to _id:
db.progress.find({username:socket},{exp:1 , _id:0},function(err,res){
find returns an array, so you will need to select the array element before accessing the field:
var findprogress = function(socket,cb){
db.progress.find({username:socket},function(err,res){
cb(res[0].exp,res[0].fraction)
})
}