Comparison between service worker and AppCache

Question

What are the core differences between service worker and AppCache. What are the pros and cons of each and when to prefer one over another .

Answer 1

In addition of what Myk Melez said, One of the main benefits of Service Workers against Application Cache is that Application Cache only works when user is disconnected from the network, so you can not manage situations of:

1- "slow network" - Your connection signal is strong, however some external entities (server, routes, etc) are delaying the transmission to your specific application.

2- "Lie-fi" (your phone shows is connected to a wi-fi or a cell network with low signal) so it seems to be connected when actually is not.

Service Workers is like a middle ware giving you control over the requests the browser is making, you can actually intercept the request and respond wherever you want, no matter you are connected or not. So you can implement "offline first" principle.