How to effectively make offline mode in web-app?

Question

JavaScript

We create a web application that will work on mobile phones. Need offline access (add to home screen and let's go). Accordingly, the application should show certain information and not swear at the absence of the Internet at all.
As I understand it, there are two chairs: appCache and Service Workers.
But, appCahe has already turned out to be Deprecated , and support for Service Workers is limited to Android, and iOs is in the span along with desktop Safari.
So far I have found a simple guide on AppCache [ ru / eng ] and in general about offline/online [ link ]
Does anyone have experience of working applications in this way? Maybe there is a ready-made fallback with Service Workers in appCache (although I doubt it very much). Well, or other practices for the implementation of the task?
Сам кейс довольно простой: есть Последние записи новостей, последние сообщения чата и небольшой справочник должны доступны быть в любом случае, даже если телефон оффлайн или по GPRS.