Sample Code for Handling Dwolla-Card.js Success/Error Responses

The docs here show sample JSON data for the response from adding a debit card funding source to a customer’s account, but are there any examples of what the javascript code to parse these responses looks like?

Specifically, I’m looking for insight on how to pull the funding sources URL out of a success response within the javascript function below:

launchDwollaDebitCardEntry(token) {
      dwolla.configure("sandbox");
      dwolla.cards.start(
        "cardContainer",
        token,
        options
      )((err, res) => {
        //TODO: parse res data to extract funding sources into a variable
      });
    }