我對編程很陌生，正在按照教程學習。我被卡住了，無法使用代碼發布新條目，也無法找到我在這里遺漏的內容。任何幫助將不勝感激。當我嘗試使用郵遞員發帖時，我收到驗證錯誤，當我嘗試獲取值時，我收到 []。編輯：錯誤消息：“msg”：“錯誤：ValidationError：first_name：first_name需要路徑。，last_name：last_name需要路徑。，電子郵件：email需要路徑?！眪// importing modulesvar express = require('express');var mongoose = require('mongoose');var bodyparser = require('body-parser');var cors = require('cors');var path = require('path');var app = express();const route = require('./routes/route');//connect to mongoDBmongoose.connect('mongodb://localhost:27017/contactlist');//on connectionmongoose.connection.on('connected', () => {  console.log('Connected to database mongoDB @ 27017');});//on errormongoose.connection.on('error', (err) => {  if (err) {    console.log('Error in DB connection' + err);  }});//port noconst port = 3000;//adding middlewareapp.use(cors());//body - parserapp.use(bodyparser.json());//static filesapp.use(express.static(path.join(__dirname, 'public')));//routesapp.use('/api', route);//testing serverapp.get('/', (req, res) => {  res.send('cutard');});app.listen(port, () => {  console.log('Server started at port:' + port);});const express = require('express');const router = express.Router();const Contact = require('../models/contacts');//retriving contactrouter.get('/contacts', (req, res, next) => {    Contact.find(function (err, contacts) {        res.json(contacts);    })});//add contactrouter.post('/contacts', (req, res, next) => {    console.log(req.body)    let newContact = new Contact({        first_name: req.body.first_name,        last_name: req.body.last_name,        email: req.body.email    });    newContact.save((err, Contact)=>{        if (err) {            res.json({ msg: ' Error: '+err});        }        else {            res.json({ msg: 'Contact added successfully' });;        }    });});