使用 axios 发布请求，给出错误 400.u

Question

所以我是构建应用程序的新手并且一直在构建提交表单，但是我的发布请求给了我一个错误 400。我知道我的数据库已连接，因为我的 GET 请求工作正常，并且我知道我的 API 有点功能因为失眠POST 请求是否正常。这是我的 apply.js 页面代码。在控制台中，状态变化出现了，所以我认为信息传递得很好。我觉得这一定是我的帖子请求在某个地方做得不好。

function Apply() {
    const [applicant, setApplicant] = useState("");
    const [address, setAddress] = useState("");
    const [loanAmount, setLoanAmount] = useState(0);

  const handleChange = ({target})=> {
    if(target.name === "username") setApplicant(target.value);
    else if(target.name === "address") setAddress(target.value);
    else if(target.name === "loanAmount") setLoanAmount(target.value);
    else console.error("error changing Applicant");
  }
  const handleSubmit = (e) => {
    e.preventDefault() 
    console.log(applicant, loanAmount, address);

    axios
    .post('http://localhost:5000/users/add',{applicant, loanAmount, address}) 
    .then(res => console.log(res.data))
    .catch(err => console.log("Error of type: " + err))

我觉得我在做一些非常愚蠢或语法上很愚蠢的事情，但这里是 user.model,js

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const userSchema = new Schema({
    username: { type: String, required: true, unique: true, trim: true, minlength: 3},
    loanrequest: {type: Number, required: true, trim: true},
    address: {type: String, required: true, trim: true },
    email: {type: String, required: false, trim: true}
});

let users = mongoose.model('User', userSchema);

module.exports = users;

这是我使用 Users.js 中的模型的路线

const router = require('express').Router();
let User = require('../models/user.model');

router.get('/', (req,res) => {
    User.find(req.params.id)
    .then(users => res.json(users))
    .catch(err => res.status(400).json('Error: ' + err));
});

router.post('/add', (req, res) => {

    const username= req.body.username;
    const loanrequest= Number(req.body.loanrequest);
    const address= req.body.address;
    const email = req.body.address;
    const newUser = new User ({
        username,
        loanrequest,
        address,
        email
     });

        newUser.save()
        .then(() => res.json('Application Added!'))
        .catch(err => res.status(400).json('Error: ' + err));
    });

module.exports = router;

如果这篇文章太长，我很抱歉。我花了大约 2 天的时间试图弄清楚我做错了什么。感谢您的帮助！

Answer 1

你有没有试过代替这段代码

const username= req.body.username;
const loanrequest= Number(req.body.loanrequest);
const address= req.body.address;
const email = req.body.address;
const newUser = new User({
    username,
    loanrequest,
    address,
    email
 });

下面的代码，我认为你不能像这样创建一个新文档，因为在上述情况下，架构将采用如下对象 {1: ..., 2: ...} 而不是所需的属性（用户名、电子邮件等...）

const userData = {
    username: req.body.username,
    loanrequest: Number(req.body.loanrequest),
    address: req.body.address,
    email: req.body.address
}
const newUser = new User(userData);