I have the following function:

    save: function (dataFeed) {
        return umbRequestHelper.resourcePromise($http.post(umbRequestHelper.getApiUrl('dataFeedBaseUrl', 'Save'), dataFeed), 'Failed to save API key');
    },

I'm calling it like this:

dataFeedResource.save(vm.dataFeed).then(function () {
            //Why is this being called when the API fails?
          ...
        }).catch( function () {
            //Why is this not being called when the API fails?
            ...
        });

Even when I return 400 or 500 error from the API, the promise is never rejected, so .catch() is never called. Why is this?

Many thanks