Suggestion: improve error reporting

[benjaminbillet]

If an error occurs during async content loading, the error message looks like:
Unexpected error while loading more content:', { line: 81832, column: 47, sourceURL: 'http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false' }

Such messages are incredibly unhelpful, given that the internal error message is swallowed and the line number is messed up internally by react-native.

The problem is caused by this line:
console.error('Unexpected error while loading more content:', error);

Here, only the content of error will be serialized by console.error, ignoring the prototype chain and thus the value of error.message (defined in Error).

A simple workaround would be to change this line by something like:
console.error('Unexpected error while loading more content:', error.toString(), error);

This is a very small change but it makes the debugging simpler.

[ide]

Thanks for the detailed report, it sounds like there are two issues at hand.

The first is that you don't have access to the actual Error object. Usually we'd expose it some way (ex: via an onLoadError prop) but in this specific case you can add error handling in your onLoadMoreAsync prop. The only other errors would be due to implementation bugs in InfiniteScrollView, which we expect not to exist but if they do (that's reality) we at least want to see them, hence the console.error call. So I don't think there's anything to change here.

The second problem is that console.error(error) prints out useless info because of how React Native serializes errors. My suggestion is to send a PR to React Native to make the console error logging more like V8's. The place to do that is here: https://github.com/facebook/react-native/blob/0dd93b62b4d1f6e570274eb7b3d7f5f557a3ea20/packager/react-packager/src/Resolver/polyfills/console.js#L379. That way all libraries and not just this one can fix the issue you reported.

[benjaminbillet]

The only other errors would be due to implementation bugs

For example, if I have some syntax error in renderLoadingErrorIndicator or in onLoadMoreAsync (e.g., something was not imported), the error will be catched by InfiniteScrollView, hiding any useful information regarding the actual error.

I agree that a better console.error logging would to the trick. Currently, I can see that the output log (react-native log-android/log-ios) displays correctly the error, thanks to the formatError function used in console.js. However, the red screen of death message is slightly different and does not include the result of formatError.