[vosper]

> Servers die, machines get unplugged, network partitions happen, etc

These things happen in backend / distributed systems. They don't really happen in the browser, which is basically a self-contained sandbox that can make network requests. The browser code needs to handle those network requests maybe failing, but that's about it in terms of dealing with unpredictability. So, it's totally reasonable to think that a web-app should never be able to crash.

[_asummers]

So if I make two API requests and get some nonsensical data that comes back, (say v1 from the first request, and v2 comes back from the second because of some bug in the backend). The program can certainly prepare itself for validating that data, and reject the v2 if it's not prepared for it, but then what do you do? To me "crashing" that entire page is a reasonable way to get around that for some programs. You as a browser can also lose Internet, in which case you also need to be prepared for things that happen on the other end depending on the circumstances of disconnection (did my request go out before it died? should I retry?). The problem is certainly more constrained, to your point, by being in a browser, but it's trivial to get your program in a nonsensical state that such that you cannot render as soon as you introduce external APIs. Perhaps Elm gets around this somehow, but I'm failing to see how.

Edit: redirection --> disconnection

[protomikron]

> The program can certainly prepare itself for validating that data, and reject the v2 if it's not prepared for it, but then what do you do? To me "crashing" that entire page is a reasonable way to get around that for some programs.

Such stuff is mostly handled via types like `Maybe APIResponse` or `Either ErrorMsg APIResponse`, so the type systems can guarantee that you handle both cases. And handling the error case (even if it's just a simple message to the user like "Error: Unable to fetch new weather data for location X/Y") is better then just crashing.

I mean it depends on your definition of crashing, but I consider it similar to undefined behaviour. So I greatly prefer

    $ ./fetch_weather $location
    panic: unable to fetch new weather data for location X/Y

to

    $ ./fetch_weather $location
    Segmentation fault

and I guess most people do (where segfault is similar to 500 Internal Server Error which is equally bad).

[skybrian]

Browser code often hangs forever and then the user has to reload the page. There might not be an error message, but this is still a bad user experience.

Personally, I'd rather have the error message.