想要仅删除对象键表单对象

Question

这是在someroute.js中添加路由。同时用教师模型填充主题模型。我只想携带老师姓名和学科名称。如何解决这个问题。

router.get('/add',function(req,res,next){
  Subject.find({},{'subname': 1, _id: 0}).populate('teacher_id', { name: 1, _id:0}).exec(function (err,rtn) {
    if(err) throw err;
    console.log(typeof rtn);
    console.log(rtn);
    res.render('admin/timetable/time-add',{ title: 'Express', subj: rtn});
  });
 });

这是用于创建选择选项的添加页面JavaScript

var subject = [<%- subj %>];

  console.log(subject);
  addOptions('teacher_id', subject);
  $("#teacher_id").on('change', function(){
      var sub = $.grep( subject, function( n, i ) {
        return n.teacher_id == $("#teacher_id").val();
      });
      addOptions('subname', sub);
  });

  function addOptions(id, arr){
      $("#"+id).children().remove();
      for(var idx in arr){
          if(idx == 0) $("#"+id).append(new Option('Select '+((id == 'teacher_id')? "Teacher": "Subject"), ''));
          if(idx == 0 || arr[idx][id] != arr[idx-1][id]){
              $("#"+id).append(new Option(((id == 'name')? arr[idx][id]:arr[idx][id]),arr[idx][id]));

          }
      }
  }