Express 代码“const app = express()”不起作用！

server.js 存档：

import * as express from "express";
import * as mongoose from "mongoose";
//inciando o app
const app = express();

//iniciando o banco de dados
mongoose.connection('mongodb://localhost:27017/program01', {useNewUrlParser: true});

//primeira rota
app.get('/',(req,res)=>{
    res.send('Hello World')
})

app.listen(3000)


==============================
console: 

*[nodemon] restarting due to changes...
[nodemon] starting `node server.js`
[nodemon] restarting due to changes...
(node:12020) ExperimentalWarning: The ESM module loader is experimental.
[nodemon] starting `node server.js`
(node:8472) ExperimentalWarning: The ESM module loader is experimental.
file:///C:/Users/USUARIO/Documents/Project%20Web/program01/server.js:4 …