[app-configuration] Adding in sample code and readme

[richardpark-msft]

No description provided.

[richardpark-msft]

@chradek , @ramya-rao-a - do we have a preference for samples? We have some that seem to live as tests and some that are standalone files.

These samples have been written so (hopefully) you can just copy and paste a single test into a project, so long as you import @azure/app-configuration

[chradek]

Is this PR to add samples for users to reference, or tests for some sample scenarios?

If the former, you can take a look at event-hubs for an example of what we do.

We should have a README in the samples folder that explains how to use any of the samples we commit. We then have sample files for various scenarios. You might be able to make these from some of the live tests, or look at what other language SDKs included with their samples.

[richardpark-msft]

Okay, I found a mid-way solution that I think is nice.

I separated out the individual samples that I've got into two separate files (helloWorld.ts and helloWorldWithLabels.ts). Those files are tied together with an index.ts in the same folder which I then use and run within the tests.

So the samples are part of the main build/test loop (which was my actual goal).

[chradek]

Since you're using await, you can rewrite this as

const result = await client.listConfigurationSettings({
  label,
  key,
  acceptedDateTime,
  fields
});

console.log("The result is:", result);

You should also give an explanation of what some of the fields are...just looking at it I'm not sure what acceptDateTime is doing, or what specifying fields will do either.

Nit: I don't think top-level await exists yet, you'd need to use await inside of an async function.

[richardpark-msft]

I modified it to e a simpler API that basically does the same thing. The listConfigurationSetting() api is a bit more complex and could use a better sample which I can add in another PR.