Custom `handleResponse` Not Called on Fetch Failure

[blaskovicz]

Firstly, thanks for the awesome library! I've been switching to React from Angular and it's starting to grow on me :smile:

I'm trying to inject a custom error message to any fetch that fails without a more specific error message so I don't need to update all my components individually.

Looking at the code, it seems that handleResponse is called as a .then(), meaning if the fetch returns a failed Promise (eg: can't connect to foo.site.com), I have no way of injecting a custom json failure message.

Do you have any suggestions of a workaround? Perhaps handleReponse could also be called on failure?

Thoughts?

[blaskovicz]

As a workaround, I had to override connect.defaults.fetch with some nasty logic.