该路由不存在！制作注册表格时出现404错误

Question

im试图通过允许用户输入电子邮件、密码和姓名来创建注册表单。我设置了一个404错误代码路线，当一条路线不存在时，由于某种原因它会出错，但我不知道是什么原因。有人能检测到这个问题吗？我也连接了mongodb，但不确定这是否会影响它。这是我的代码。

const { validationResult } = require('express-validator')
const User = require('../modelSchema/User')
const signUp = (req, res) => {

const errors = validationResult(req)
if(!errors.isEmpty()) return res.status(400).json({ errors: errors.array()})
//new instance of user
const user = new User({ 
name: req.body.name, 
email: req.body.email, 
password: req.body.password })
//save the user 
user.save()
.then(data => {
response.json(data)
console.log(data)
})
.catch(err => {
response.json(err)
})

}

module.exports = { signUp }

这是我的后端代码，我在其中导入mongodb，我的404错误代码在其中检测到一个坏路由

const express = require('express')
const cors = require('cors')
const app = express()
const mongoose = require('mongoose')
const dotenv = require('dotenv')
const routes = require('./routes/index')
//middleware
app.use(cors())
dotenv.config()
mongoose.connect(process.env.DATABASE_ACCESS, () => console.log('Database Connected'))
//bodyParser
app.use(express.json({ extended: false }))
app.get('/', (req, res) => {
res.send('Hello World!');
})
app.all('*', (req, res) => res.send('That route does not exist!'))
app.use('/app', routes)
app.listen(4000, () => console.log('Server is listening on port 4000'))

这就是我的路线。现在我只有我的注册路线，但稍后我将实现一个登录路线

const express = require('express');
const { check } = require('express-validator')
const { signUp } = require('../controllers/users');
const router = express.Router();
router.post('/signup', [
check('name', 'Please Enter your Name').not().isEmpty(),
check('email', 'Please Enter your Email').isEmail(),
check('password', 'Please Enter your Password').isLength({ minLength: 6})
], signUp)
module.exports = router;

Answer 1

const signUp = (req, res) => {

const errors = validationResult(req)
if(!errors.isEmpty()) return res.status(400).json({ errors: errors.array()})
//new instance of user
const user = new User({ 
name: req.body.name, 
email: req.body.email, 
password: req.body.password })
//save the user 
user.save()
.then(data => {
res.json(data)
console.log(data)
})
.catch(err => {
res.status(400).json(err)
})

}