Error raised if someone goes offline and attempts a request

[troym9731]

Hi! I'm running into an issue where, if someone attempts a request while they are offline, result.headers on line 40 blows up because err.response is undefined. I'm unsure of the proper way to go about fixing this, or if there is something I should be doing with the axios instance before passing it to axios-fetch to avoid this issue altogether.

Any help would be greatly appreciated!

[mdlavin]

That's a case I haven't thought of before. This project is based around having axios-fetch behave just like fetch does, so my first question is "How does fetch behave in the offline case?".

If you know that, I have a feeling that the code here could be updated to match the fetch behavior if .response is missing

[troym9731]

So it seems like it fails with a TypeError, and is one of the few cases that fetch returns a rejected promise.

Here is a post I found detailing the different error messages based on the browser: https://medium.com/vinh-rocks/how-to-handle-networkerror-when-using-fetch-ff2663220435

And here is the line of a test case in node-fetch for handling a network failure: https://github.com/node-fetch/node-fetch/blob/master/test/main.js#L110

So what would be your preferred path forward?

[mdlavin]

The simplest thing I can think of that might work is to change:

} catch (err) {
  result = err.response;
}

into

} catch (err) {
  // Non-HTTP failures should be re-thrown. This will handle lower level network failures
  if (!err.response) throw err;
  // HTTP level failures can be translated into fetch style responses
  result = err.response;
}

Is it possible for you to try a change like that and see if it fixes your problem?

[troym9731]

That appears to work! Would you like me to open a PR with those changes, or would it be simpler for you to just commit the change yourself?

[jkdowdle]

Unless someone feels otherwise going to go ahead and close this issue. The proposed solution was implemented in #78 and released in @lifeomic/axios-fetch@2.0.2 #79