app.js

//Understanding Middleware
"use strict";
const express = require("express");
const app = express();
const cors = require("cors");

const { sup, how } = require("./middle");

app.use(sup);
app.use(cors());

app.get("/", how, sup, (req, res) => {
  res.send({ data: "hi" });
});

app.listen(3000, err => {
  if (err) {
    console.log(err);
    return;
  }
  console.log("listening on port 3000");
});

middle.js

const sup = (req, res, next) => {
  console.log(req.method);
  console.log("sup");
  next();
};

const how = (req, res, next) => {
  console.log("how you doin?");
  next();
};

module.exports = { sup, how };