Ido Shamun wrote a nice tutorial on how to create an effective method for caching data using Vue.js.

vue data offline

Offline capability is a must and honestly not so hard to achieve as you will see in this blog post. Basically it means that your application can work even without connectivity at all, of course it does not mean that all features will be provided but a subset. For this purpose we can use Service Workers, Web SQL, IndexedDB and many other tools provided by the browser. I use localForage as an abstraction for an offline storage instead of working with low level API.