text: const express = require("express");
  const Calculator = require("./service/calculatorService.js");
  
  const app = express();
  
  app.use(express.json());
  
  const calc = new Calculator();
  
  app.post("/add", (req, res) => {
    const { a, b } = req.body;
    res.json({ result: calc.add(a, b) });
  });
  
  app.post("/sub", (req, res) => {
    const { a, b } = req.body;
    res.json({ result: calc.sub(a, b) });
  });
  
  app.post("/mul", (req, res) => {
    const { a, b } = req.body;
    res.json({ result: calc.mul(a, b) });
  });
  
  app.post("/div", (req, res) => {
    const { a, b } = req.body;
    res.json({ result: calc.div(a, b) });
  });
  
  app.get("/", (_, res) => {
    res.json({
      description:
        "It's possible perform sum, sub, div and mul operations, just make a post request and pass the a and b values",
    });
  });
  
  app.listen(3000, () => {
    console.log("Server is running on port 3000");
  });
  