#請益 Node.js 的 @types/express 與 express 的差異？
我想使用 Typescript 開發網站，使用 @types/express
但為什麼還要安裝 express ?
那我是不是每一個 @types/* 都要安裝對應的 npm package ???
目前 package.json 非常單純：
{
"devDependencies": {
"@types/express": "^4.17.13",
"@types/node": "^18.7.13",
"nodemon": "^2.0.19",
"typescript": "^4.8.2"
},
"dependencies": {
"dotenv": "^16.0.1",
"express": "^4.18.1",
"pg": "^8.8.0",
"reflect-metadata": "^0.1.13",
"typeorm": "^0.3.8"
}
}
就是這個 @types/express 和 express 造成我的疑問
我的認知是 Typescript 可依tsconfig.json編譯成 JavaScript 給 Nodejs 運行
也就是說我把 @types/express 跑 tsc app.ts 編譯成 app.js 給 Nodejs 理論上應該可以成功
但編譯後 Nodejs 會認不出 express 是甚麼，還要另外裝 express ?? (what?)
另一個問題
那我不編譯 TS 可以直接運行 @types/express server 嘛？直接捨棄編譯那塊
```
Romain Bruckert(answered)：
I'v run into this issue myself and found out you also have to have the actual nodeJS module installed as well as its typing.
So when you have correclty configured typescript and your project, you need ot install both the nodeJS dependency as well as the @types dependecy.
```
