Javascript 为什么'；：服务器'；和'；：客户'；找不到？

我正在尝试从db.json获取数据

这是我的db.json文件：

{
    "posts": [
      { "id": "react-hooks", "title": "React Hooks", "content": "The greatest thing since sliced bread!", "author": "ali" },
      { "id": "react-fragments", "title": "Using React Fragments", "content": "Keeping the DOM tree clean!", "author": "ali" }
    ],
    "users": [
      { "id": 1, "username": "ali", "password": "********" }
    ],
    "themes": [
        { "id": 1, "primaryColor": "deepskyblue", "secondaryColor": "coral" },
        { "id": 2, "primaryColor": "orchid", "secondaryColor": "mediumseagreen" },
        { "id": 3, "primaryColor": "darkslategray", "secondaryColor": "slategray" }
    ]
  }

在这之后，我执行了npm安装——保存json服务器和npx json服务器——查看服务器/db.json，并编辑了“脚本”：部分如下：

"start:server": "npx json-server --watch server/db.json",
"start:client": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"

然后我执行了npm安装——并发保存，然后在脚本中添加了这一行：

"start": "npx concurrently \"npm run start:server\" \"npm run start:client\"",

然后我执行了npm安装——保存http代理中间件，然后我创建了setupProxy.js并输入以下代码：

const { createProxyMiddleware } = require('http-proxy-middleware');
module.exports=function(app){
    app.use(createProxyMiddleware('/api',{
        target:'http://localhost:5000',
        pathRewrite:{'^/api':''}
    }))
}

然后，我执行了npm安装，之后，当我执行npm start时，它显示以下错误：

The system cannot find the file :client.
[5] start:client exited with code 1
[2] The system cannot find the file :server.
[2] start:server exited with code 1
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! reacttutorial@0.1.0 start: `npx concurrently "npm run start:server" "npm run start:client"`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the reacttutorial@0.1.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

有两个windows警报显示：找不到“：server”和“：client”

我已经通过执行npx create react app reacttutorial创建了全新的应用程序。我的想法快用完了。谁能帮我一下吗？

看看这个回复

所以你加入了

"scripts": {
  "dev": "concurrently \"npm run server\" \"npm run react\"",
  "server": "npx json-server --watch server/db.json --port 4000 --routes server/routes.json",
  "react": "react-scripts start",
  ...}

并使用npm run dev或npm start

为我工作

---

并且在setupProxy.js文件中使用createProxyMiddleware代替proxy

Wow，那是很久以前的事了，我已经在不同的终端上解决了这个问题。但我会检查你的解决方案。看到有人回答这样一个老问题真是太酷了，我想谢谢你，不经检查就接受你的回答。又来了