node.js - Mongoose(mongo)，复制文档

Question

正在尝试复制文档。首先我找到它。然后删除_id。然后将其插入。但calculation._id仍然存在。所以我抛出了重复错误。我究竟做错了什么？

mongoose.model('calculations').findOne({calcId:req.params.calcId}, function(){
      if(err) handleErr(err, res, 'Something went wrong when trying to find calculation by id');

      delete calculation._id;
      console.log(calculation); //The _.id is still there
      mongoose.model('calculations').create(calculation, function(err, stat){
        if(err) handleErr(err, res, 'Something went wrong when trying to copy a calculation');
        res.send(200);
      })
    });

Answer 1

从 findOne 返回的对象不是普通对象，而是 Mongoose 文档。您应该使用 {lean:true} 选项或 .toObject() 方法将其转换为纯 JavaScript 对象。

mongoose.model('calculations').findOne({calcId:req.params.calcId}, function(err,calculation){
  if(err) handleErr(err, res, 'Something went wrong when trying to find calculation by id');

  var plainCalculation = calculation.toObject();


  delete plainCalculation._id;
  console.log(plainCalculation); //no _id here
});