Express.js adalah framework minimalis untuk membuat web server di Node.js.

Setup dasar:

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

// Route GET /
app.get("/", (req, res) => {
  res.json({ message: "Halo dari Express!" });
});

// Route GET /users
app.get("/users", (req, res) => {
  res.json({ users: ["Budi", "Siti", "Andi"] });
});

app.listen(3000, () => {
  console.log("Server berjalan!");
});

Konsep utama:

• app.get(path, handler) — menangani GET request
• app.post(path, handler) — menangani POST request
• req — object request (data dari client)
• res — object response (data ke client)
• res.json(data) — kirim response JSON
• res.status(code) — set status code

Request & Response:

app.get("/users/:id", (req, res) => {
  const id = req.params.id;    // Path parameter
  const page = req.query.page; // Query string ?page=2
  res.json({ id, page });
});

app.post("/users", (req, res) => {
  const body = req.body;       // Request body (JSON)
  res.status(201).json(body);
});