How to get the dynamic field data into the API Request

I have created a Dynamics Field in the Input designed the code is below. The result of this Dynamic field can return ~ 100 fields that can vary and not all values need to be filled in. I want to know how to get the field name that has a value included to pass into the body of the API call. 

My Code to build the Dynamic Field is the following and it successfully works.

// Configure a request to an endpoint of your api that
// returns custom field meta data for the authenticated
// user.  Don't forget to congigure authentication!

const options = {
  url: 'https://{{APIcall}}',
  method: 'GET',
 headers: {
    'Content-Type': 'application/json',
    'Accept': 'application/json',

  },
  params: {

  }
}

return z.request(options).then((response) => {
    response.throwForStatus();
    const results = [];
    const fetchFields = (fieldArr, prefix) => {
        fieldArr.forEach(fieldInfo => {
            results.push({
                'key': prefix && prefix.length ? (`${prefix}:${fieldInfo.name}`) : fieldInfo.name,
                'type': fieldInfo.dataType,
                'label': fieldInfo.name
            });
            if (fieldInfo.fields && fieldInfo.fields.length) {
                fetchFields(fieldInfo.fields, fieldInfo.name);
            }
        });
    };
    fetchFields(response.json.fields)
    return results;
});

 I then get a large list of field in the zapier editor which is correct.

But how would I pass the results into the API Call if someone just filled the city like above? I would now know what the field name are or values until someone tries the zap.

Chris