测试登录，但得到401未经授权的响应；使用JWT

Question

当前在创建登录功能时遇到问题。每当我提交凭据时，我都会继续收到401响应。检查错误消息后，我在用户服务功能的登录功能中看到了错误。

我已经检查了项目的不同区域，即BASE_URL导致关联的路由，从而导致了我的用户控制器的关联模型。我清理了所有错字。我还通过控制台记录了可以给我更多信息的任何区域

//Login.jsx

//The following code, was presented, in the console. 

import React, {Component} from 'react'
import { Link } from 'react-router-dom'
import userService from '../utils/userServices'


        handleSubmit = async (e) => {
            e.preventDefault();
            try {
                await userService.login(this.state);
                console.log(userService.login())
                this.props.handleSignupOrLogin();
                this.props.history.push('/');
            } catch(err){
                console.log(err + "login err")
               console.log('Invalid Credentials');
            }
            //TODO check to see if passing a history prop will work
        }

//userServices.jsx
//res.ok returned false

import tokenService from './tokenServices';



function login(creds){
    return fetch(BASE_URL + 'login',{
        mode:'cors',
        method: 'POST',
        headers: new Headers({'Content-Type': 'application/json'}),
        body: JSON.stringify(creds)
    })
    .then(res => {
        console.log(res)
        console.log(fetch)
        if(res.ok) return res.json();
        console.log(res.ok)
        throw new Error('Bad Credentials');
    })
    .then(({ token }) => {tokenService.setToken(token)});
}


//routes/users.js

const express = require('express');
const router = express.Router();
const userCtrl = require('../controllers/user');



//public routes
router.post('/signup', userCtrl.signup)
router.post('/login', userCtrl.login)

module.exports = router;


//controllers/user.js

const User = require('../models/user');
const jwt = require('jsonwebtoken');
const SECRET = process.env.SECRET;

...

async function login(req, res) {
    try {
      const user = await User.findOne({username: req.body.username});
      if (!user) return res.status(401).json({err: 'bad credentials'});
      console.log(user)
      user.comparePassword(req.body.password, (err, isMatch) => {
        if (isMatch) {
          const token = createJWT(user);
          res.json({token});
        } else {
          return res.status(401).json({err: 'bad credentials'});
        }
      });
    } catch (err) {
      console.log(err)
      return res.status(401).json(err);
    }
  }

The expected output
 here Response 

    `{
    type: "basic", 
    url:"http://localhost:3000/routes/users/login", 
    redirected: false, 
    status: 401, 
    ok: true, 
    …}
    `

but instead got

Response {

    `type: "basic", 
    url: "http://localhost:3000/routes/users/login", 
    redirected: false, 
    status: 401, 
    ok: false, 
    …}`