Move request error message from the worker to the main thread

[kettanaito]

Scope

Improves an existing behavior

Compatibility

• This is a breaking change

Feature description

Right now, whenever any request errors, MSW will produce the error message saying that something went wrong and it's unlikely an issue with MSW. That error message is really meant only for one purpose: to facilitate exceptions rising from the request handlers. But since it's just a try/catch block around the entire fetch event in the worker, that message also gets printed when extraneous request error, including requests that are meant to error by the developer.

Expected behavior

• The current message is printed only upon an exception originating from the request handlers the user has defined.
• The current message is not printed upon any other request error, if those requests or their handling has nothing to do with MSW.

References

msw/src/mockServiceWorker.js

Lines 128 to 136 in e87e00b

	// At this point, any exception indicates an issue with the original request/response.
	console.error(
	`\
	[MSW] Caught an exception from the "%s %s" request (%s). This is probably not a problem with Mock Service Worker. There is likely an additional logging output above.`,
	request.method,
	request.url,
	`${error.name}: ${error.message}`,
	)
	}),

[kettanaito]

@thepassle, thanks for suggesting this. I opened the issue to keep track of it. If you have any feedback to share on this or how it should behave, please let me know. Thanks.

[thepassle]

including requests that are meant to error by the developer.

Additionally: requests that are not related to MSW at all

But otherwise this looks good to me :) Thanks for creating the issue, I hadn't got round to it yet!