The author of the text describes how to build a Progressive Web App (PWA) using Node.js, Hoodie, and Service Workers. They start by setting up an environment with Node.js and npm, then install the Hoodie package for offline-first functionality. The app allows users to add items to a shopping list, save it, and view a summary of the totals on a separate page. The app uses Hoodie's storage API to store data locally on the device and syncs it with the server when there's a network connection. To make the app work offline, they use Service Workers to intercept requests and respond with cached responses. They also use the Cache API to cache assets and serve them from the service worker. The app is still incomplete as a PWA but lays the foundation for future development.