Variables inside $push not working in Mongoose

Question

I have this Schema

courses: [],
workshops: [],
events: [],
semesters: {
  sem1: { cie1: [], cie2: [], cie3: [], final: [] },
  sem2: { cie1: [], cie2: [], cie3: [], final: [] },
  sem3: { cie1: [], cie2: [], cie3: [], final: [] },
  sem4: { cie1: [], cie2: [], cie3: [], final: [] },
  sem5: { cie1: [], cie2: [], cie3: [], final: [] },
  sem6: { cie1: [], cie2: [], cie3: [], final: [] },
  sem7: { cie1: [], cie2: [], cie3: [], final: [] },
  sem8: { cie1: [], cie2: [], cie3: [], final: [] },
},

I want push data in CIE's and Final Array of each sem I use this to do

  if(type==="cie"){
    const path = "semesters.sem"+semester+".cie"+num;
    // const path = "semesters.sem1.final.";
    Student.update({reg_no: req.body.regno},{$push:{path:req.body.submarks}},function(err,result){
        res.send(err);
    });
  }
  if(type === "final"){
    // const path = "semesters.sem"+semester+".final";
    const path = "semesters.sem1.final.";
    Student.update({reg_no: req.body.regno},{$push:{path:req.body.submarks}},function(err,result){
      res.send(result);
  });
  }

I use path variable to define the path but it's not working when I give path as String in push it works but this does not works when I give as string variable. Help Me Resolving this.

Answer 1

To use varibale as object key, you need to do something like:

{ $push: { [path]: req.body.submarks } }