Node.js貓鼬“ object.newProperty”無法向對象添加新屬性

Question

我正在使用mongoose從Mongo獲取字段，並嘗試為返回的結果分配新的鍵。 但是，當我在分配新密鑰后登錄該對象時，該密鑰不在記錄的對象中。

奇怪的是，如果我登錄obj.newKey，它會按預期方式記錄下來，但是在記錄整個對象時似乎缺少該對象。

const express = require('express');
const router = express.Router({ mergeParams: true });

const V = require('../../../models/KB/V');

router.post('/fetch-v', async (req, res) => {
  const { idSC, idDC, idP, from, to } = req.body.tp;
  const nds = Math.ceil((to - from) / 86400000 + 1);
  // All set. Now query database for visas:
  let vs = await V.find({
    idSC,
    idDC,
    idP
  }).exec();
  vs.map(v => {
    v.nds >= nds ? (v.applicable = true) : (v.applicable = false);
    console.log('v.applicable:', v.applicable); // Refer Log 1
  });
  console.log('vs:', vs); // Refer Log 2
  return res.send({ success: true, vs });
});

日志1

v.applicable: true
v.applicable: false

日志2

{
  "success": true,
  "vs": [
      {
          "_id": "5d51acd41255b4499021bffa",
          "idSC": "5d4e9273928a933e44ba8b56",
          "idDC": "5d4e7318c8562b2bf6e4c33f",
          "idP": "5d4e74742e0e3c2d2ab5428e",
          "nds": 89,
          "createdAt": "2019-08-12T18:15:48.329Z",
          "updatedAt": "2019-08-12T18:15:48.329Z",
          "__v": 0
      },
      {
        "_id": "5d51acd41255b4499021bffb",
        "idSC": "5d4e9273928a933e44ba8b56",
        "idDC": "5d4e7318c8562b2bf6e4c33f",
        "idP": "5d4e74742e0e3c2d2ab5428e",
        "nds": 2,
        "createdAt": "2019-08-12T18:15:48.329Z",
        "updatedAt": "2019-08-12T18:15:48.329Z",
        "__v": 0
    }
  ]
}

Answer 1

await V.find({...})返回mongoose.Document數組，所以如果你想要新的屬性添加到它的元素，你可以使用.lean（）就可以了。

例：

let vs = await V.find({...}).lean();