explain router.get("/:id(\\d+) code example

Example: explain router.get("/:id(\\d+)

let express = require('express');
let app = express();

app.get('/api/Widgets', (request, response, next) => {
    // Business logic goes in here...
    // then we send something in the response, maybe some JSON!
    response.json({ widgets: [ { id: 1, name: 'foo' }, { id: 2, name: 'bar' } ] });
    // Note that we DO NOT all next() unless we want another route to also fire (usually we do not).
});

app.listen(3000);