Javascript: How to attribute the value of the each item in dataframe

Question

I would like to assign grades for each subject, the objective is to retrieve a subject and its corresponding grade in dataframe

subject	grades
maths	15
French	12
English	10
Science	08

I will obtain that:

{
  "values": {
    "maths": 15,
    "French": 12,
    "English": 10,
    "Science": 08
  }
}

for (var i = 0; i<data.length; i++){    
    trans = data["subject"][i];        
    res = data["grades"][i];    
return cor = {'values':{             
                  res : trans   }}  
return cor
}