Abortable fetch

[jklemmack]

To address UserVoice request Support AbortController API in servicestack-client, and to add a feature analogous to AxiosJS's cancellation, this PR adds support for an optional request config parameter signal, of type AbortSignal.

This is a cleanup & reissue of PR #19

Example usage:

let controller = new AbortController();
const signal = controller.signal;

let client = new JsonServiceClient(...)
let result = client.get(request, null, signal )
.then(response => {})
.catch((error) => {})

signal.abort();

[mythz]

@jklemmack Is this PR ready to merge? Or if you're still working on it drop a comment later to let me know when it's ready.

I'm usually hesitant to add dependencies in case it breaks an environment. Can you also check that the UMD build still works, i.e:

<script defer src="dist/servicestack-client.umd.js"></script>

[jklemmack]

It should be good to go, but I'll admit there's some risk. The majority of the tests fail for me since the test URL endpoint isn't live currently. The additional AbortController dependency is only added as a devDependency to support testing.

Right now I'm getting an error running publish which I think I've traced to inject-umd.sh

sed: 1: "dist/servicestack-clien ...": extra characters at the end of d command

I'm not a Mac/linux guy, so I'm hitting a nice brick wall currently.

[mythz]

I'm not a Mac/linux guy, so I'm hitting a nice brick wall currently.

I'm running this on Windows. To build the library I'm just running npm run publish package.json script which uses WSL's bash inject-umd.sh to run the script. I've deployed an update very recently so you should be able to run npm run publish in your local branch to build the /dist assets.