let express = require('express');

let app = express();

app.use(express.static('public'));

app.listen(3000, () => {
  console.log("http://localhost:3000/");
});

let express = require('express');

let app = express();

app.use(express.static('public'));

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

Change port to use env variable.
Change port to use env variable.
