Express Installation ও প্রথম Server

# project directory তৈরি
mkdir my-express-app
cd my-express-app

# package.json তৈরি
npm init -y

# express install
npm install express

# dev dependency (অটো-রিস্টার্টের জন্য)
npm install --save-dev nodemon

{
  "name": "my-express-app",
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon index.js"
  }
}

const express = require("express");
const app = express();
const PORT = process.env.PORT || 3000;

app.get("/", (req, res) => {
  res.send("Hello, Express!");
});

app.listen(PORT, () => {
  console.log("Server চালু: http://localhost:" + PORT);
});

npm run dev

# Output: Server চালু: http://localhost:3000

import express from "express";
const app = express();

// package.json-এ "type": "module" যোগ করুন */

app.get("/", (req, res) => res.send("ESM Mode!"));
app.listen(3000);

my-express-app/
├── index.js            # entry point
├── package.json
├── .gitignore
├── public/            # static files (css, images)
├── views/             # template files (EJS, etc.)
├── routes/            # route handlers
├── middleware/        # custom middleware
├── models/            # database models
└── controllers/       # business logic