Sounds great! I've made the changes locally per your suggestions. I'll add some tests and update the README within the week.

I added a test to ensure config doesn't throw if labels are defined. I'm not sure if or what other tests you might be looking for to test the label filtering functionality. I'm not very experience with mocks so any direction or assistance you can provide with awesome.

I added a test to ensure config doesn't throw if labels are defined. I'm not sure if or what other tests you might be looking for to test the label filtering functionality. I'm not very experience with mocks so any direction or assistance you can provide with awesome.

We could use the toBeCalledWith function to assert that we are passing the AZURE_APP_CONFIG_LABELS to client.listConfigurationSettings():

expect(appConfigListMock).toBeCalledWith(
  expect.objectContaining({
    labelFilter: AZURE_APP_CONFIG_LABELS,
  })
)

Another good feature to have is allowing the label filter to be defined programmatically, just like the connectionString:

Then we could use it like this:

await dotenvAzure.config({ labels: 'production,development' })

or

await dotenvAzure.config({ labels: ['production', 'development'] })

The CI is failing because of prettier, just run the script below, commit the changes and it should be fixed:

npm run format