I want to update an array document in a movie collection of mongoDB. However i can't pass the index i of the for loop as the property to update. e.g. it works when i update with "review.0.rating" but it doesn't if i update with review.i.rating. Any ideas??

DB collection

for (var i=0; i< movie[0].review.length; i++){
            //if the user made rating before, update his rating
            if(movie[0].review[i].user === req.body.userID ){  
              await db.collection('movies').updateOne(
                {_id:ObjectId(req.body.movieID)},
                {$set: {review.i.rating: idx} }
              );
              
            }
            
          }