Very interesting and new project no download no install and no update with the ability to work off line concept is really interesting , an app store for progressive web apps is unique idea . I still would like to know the idea behind a cloud based app that can work offline too ! how this gonna be achieved ?
Cloud based because it used through web. You will not have to download it. Just like browsing normally in the internet which does not consume your device memory. When you search something in the web, you can open as much windows as you can but your device memory will not be affected, unlike installed applications, they are in your system, has occupied part of your storage.
You clearly stated it,Gracechen! Progressive Web Apps are developed with HTML5, CSS3, and JavaScript and they are known as "Service Workers" which sends requests and caches the responses.This is responsible for its offline feature.
Here i found some explanations with regard to how PWAs work offline:
"Provide Offline Support
One of the biggest problems with using the mobile web is that it must be connected to the internet. In order to provide a completely app-like experience, a PWA must be available and work offline. PWAs provide offline support via service workers, which are scripts that a web browser runs separately from and in the background of a web page. The service worker sends requests and caches the responses. In other words, a service worker doesn’t just store application data in random access memory; instead, it persists this data to the device’s file system or the browser’s internal databases. In the event that the browser’s internet connection fails, it can continue to operate offline. Service workers can also provide support for push notifications and updates."
Source:
https://applitools.com/blog/progressive-web-apps
