Angular has very good documentation with a good example. A library helps to run the real application as a tutorial without a server. The library is in-memory-web-api. It looks like a ready solution. It is a great idea. But it has been done specifically for the tutorial. There are cases where we work off-line. So I investigate the case. This is a standard case for Progressive Web Applications(But not this time). In this case, we have some extra logic for off-line behavior. There are three different variants:
