如何创建并配置NodeTS(TypeScript NodeJS)项目？启动报错求助

我正在搭建并运行一个简单的TypeScript Node.js项目，相关代码如下：

server.ts #

import express from 'express';

const app = express();
const PORT = 3000;

app.listen(PORT , ()=>{
    console.log('Server is listening on port $PORT');
});

tsconfig.json #

{
  "compilerOptions": {
  
    "target": "esnext",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */

    "module": "commonjs",                                /* Specify what module code is generated. */
    "rootDir": "./src",                                  /* Specify the root folder within your source files. */
    "moduleResolution": "node",                       /* Specify how TypeScript looks up a file from a given module specifier. */

    "outDir": "./build",                                   /* Specify an output folder for all emitted files. */
    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
    "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */

    "strict": true,                                      /* Enable all strict type-checking options. */
    "skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
  }
}

package.json #

{
  "name": "back",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "nodemon build/server.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@types/express": "^4.17.13",
    "express": "^4.18.1",
    "mongoose": "^6.5.0",
    "nodemon": "^2.0.19"
  }
}

执行npm start时，出现以下错误：

> back@1.0.0 start       
> nodemon build/server.js

[nodemon] 2.0.19
[nodemon] to restart at any time, enter `rs`      
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,json        
[nodemon] starting `node build/server.js index.js`
node:internal/modules/cjs/loader:936
  throw err;
  ^

Error: Cannot find module 'C:\Users\A\\Test\back\index.js'
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:77:12)
    at node:internal/main/run_main_module:17:47 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}
[nodemon] app crashed - waiting for file changes before starting...

问题原因及解决方法 #

1. package.json main字段冲突
   package.json中main设置为index.js，但实际编译后的入口是build/server.js。nodemon会自动把main字段的值作为额外参数传给node，导致执行命令变成node build/server.js index.js，node尝试加载不存在的index.js从而报错。

   • 解决：将package.json里的main字段改为build/server.js，或者直接删除该字段（因为scripts中已经明确指定了启动入口）。

2. 缺少TypeScript编译步骤
   报错信息显示nodemon尝试启动build/server.js，但如果还没执行TypeScript编译，该文件可能不存在或内容异常。

   • 解决：
     • 先安装TypeScript依赖：npm install typescript --save-dev
     • 在package.json的scripts中添加编译命令，并修改start命令确保先编译再启动：

       "scripts": {
         "test": "echo \"Error: no test specified\" && exit 1",
         "build": "tsc",
         "start": "npm run build && nodemon build/server.js"
       }
       

     • 或者使用ts-node直接运行TypeScript文件，省去手动编译步骤：安装ts-node和@types/node，将start命令改为nodemon --exec ts-node src/server.ts

3. server.ts模板字符串错误
   当前console.log使用单引号包裹字符串，$PORT无法被解析为变量值，需要改成反引号实现模板字符串解析：

   console.log(`Server is listening on port ${PORT}`);
   

内容的提问来源于stack exchange，提问作者lovecode