使用 Javascript 语法并使用 Postman 测试 API

Question

各位专家大家好，我正在尝试使用以下 javaScript 代码连接到 postamn，

然而，当我运行 nodeman 时，正常连接似乎没问题，当我向邮递员发送 GET 请求时也没有错误，确实工作正常，我不知道我做错了什么在 POST API 请求下，我尝试使用 ES6 早期语法广告，就像我现在使用 ES6 一样，但似乎不起作用。

请在下面找到我的 app.js 文件中的代码

    const express = require ('express');
const app = express();
const bodyParser = require('body-parser')

const mongoose = require('./database/mongoose');
const user = require('./database/models/user');


/*
install CORS: Cross Origin Request Security
This is basically used to run two ports on same server, 
i.e Front-End: running on localhost:4200 which is using angular framework
BackEnd: localhost: running on 3000- backend api using nodejs, express
*/
app.use(bodyParser.json());

app.use ((req, res, next) =>{
  res.header("Access-Control-Allow-Orgin", "*");
  res.header("Access-Control-Allow-Methods", "GET, POST, HEAD, OPTIONS, PATCH< DELETE" );
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
  
});

// app.use(express.json());
// app.get('/user', (req, res) => {
  //     person.find({})
  //     .then(user => res.send(user))
  //     .catch ((error) => console.log(error));
  // })
  app.get('/', (req, res)=> {
      res.send("hello world");
  });


  app.post('/register', (req, res) => {

    // (new User ({
    //   'firstname': req.body.firstname,
    //   'lastname': req.body.lastname,
    //   'email': req.body.email,
    //   'password': req.body.password
    // }))

    // .save()
    // .then((user) => res.send(user))
    //  .catch((error) => console.log(error));
    const firstname = req.body.firstname;
    const lastname = req.body.lastname;
    const email = req.body.email;
    const password = req.body.password;
    
    
    const user = new User();
    user.firstname = firstname;
    user.lastname = lastname;
    user.email = email;
    user.password = password;
    
    user.save((err, result ) => {
      if(err){
        console.log("There is error adding user to database");
        res.sendStaus(500);
      }
      res.sendStatus(200);
    })
    
  });
  
  
  app.listen(3000, () => console.log("Server is Connected to port 3000"));

另外请问我遇到的错误，我也是这个开发者的新手，有人可以纠正我吗？

ReferenceError: User is not defined
at C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\app.js:54:18
at Layer.handle [as handle_request] (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\layer.js:95:5)
at next (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\route.js:137:13)
at Route.dispatch (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\route.js:112:3)
at Layer.handle [as handle_request] (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\layer.js:95:5)
at C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:281:22
at Function.process_params (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:335:12)
at next (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:275:10)
at C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\app.js:21:3
at Layer.handle [as handle_request] (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\layer.js:95:5)
at trim_prefix (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:317:13)
at C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:284:7
at Function.process_params (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:335:12)
at next (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\express\lib\router\index.js:275:10)
at C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\body-parser\lib\read.js:130:5
at invokeCallback (C:\Users\tapesh.patel\Desktop\Website\Kare-app\BackEnd\node_modules\raw-body\index.js:224:16)

我认为 Jason 可能存在解析问题，所以我在使用 express.json 将代码解析为 json 时使用了 Bodyparser。我猜这两个在做同样的工作。

仍然不知道 JavaScript 缺少什么。如果有高手指正，帮助学习，将不胜感激

谢谢塔佩什

Answer 1

您已经导入了名称为 user 的架构，而您正试图使用名称为 User

的架构

使用 Javascript 语法并使用 Postman 测试 API

while using Javscript syntax and Testing API using Postman

javascript

node.js

angular

express

mean-stack