text: const express = require("express"),
      app = express(),
      port = 3000,
      option = {
          root: __dirname + "/html",
      };
  app.use("/public", express.static("public"));
  //http://localhost:3000/
  app.get("/", function (req, res) {
      res.sendFile("index.html", option);
  });
  //http://localhost:3000/products
  app.get("/products", function (req, res) {
      res.send(
          `<ul>
              products list
              <li>produit 1</li>
              <li>produit 2</li>
          </ul>`
      );
  });
  //http://localhost:3000/products/5465
  app.get("/products/:id/", function (req, res) {
      const id = req.params.id;
      res.send("product id : " + id);
  });
  //http://localhost:3000/products/5465/2
  app.get("/products/:id/:size", function (req, res) {
      const id = Number(req.params.id);
      const size = Number(req.params.size);
      res.send("products price : " + id * size);
  });
  app.listen(port, () => {
      console.log(`Server started on port ` + port);
  });
  