Ie11 support

[kieran-allen]

Helps resolve some bugs: #47

• Downgrade the version of fetch-mock to v6.5.2. This is due to an issue with newer versions of the library which use Proxy.
• Update tests
• Update the gotchas section of the readme to inform the reason for downgrading the version of the fetch-mock library.

[grug]

First of all - thank you so much for contributing this!

I'm just not sure I'm alright with rolling back the version of fetch-mock that far. I'm aware of some of the changes that @wheresrhys is doing with it and it will make for better testing if we can keep the version up to date.

What's the issue here? Is it that Proxy needs polyfilling? If so, maybe the gotcha here for ie11 users is that they need it polyfilled.

What are people's thoughts?

[kieran-allen]

That's a fair point!

Yeah, it looks like Proxy would need polyfilling for this to work nicely with ie11.

https://github.com/GoogleChrome/proxy-polyfill is something that does exist ( although I haven't looked into it yet ).

Might be worth looking into it.

[wheresrhys]

The PR in whatwg-fetch to fix all this has been merged, and hopefully there will be a patch release soon. Following that fetch-mock should be compatible with the proxy polyfill

[grug]

Perfect - thanks for that info @wheresrhys :)

[github-actions]

Hi there :) This PR hasn't received any attention in a while. Can it be closed or does it require more work?