How to create a person and set fields & email on the new person

app.js

var https = require("https");

 function callBandWindowAPI( requestOptions, data ) {
    return new Promise((resolve, reject) => {
        var postReq = https.request(
            requestOptions,
            function(response) { // console.log('\n\nin fun...', response);
                const { statusCode } = response;
                if (statusCode >= 300) {
                    reject(
                        new Error( response.statusMessage )
                    );
                }

                const chunks = [];

                response.on('data', (chunk) => {
                    chunks.push(chunk);
                });

                response.on('end', () => {
                    const result = Buffer.concat(chunks).toString();
                    resolve( JSON.parse(result) );
                });

            }
        );

        if (data != null) {
          postReq.write( JSON.stringify(data) );
        }

        postReq.end();
    })
}

const api_host = "YOUR_ACCOUNT.shopwindow.io";
const auth_un = "YOUR_API_USERNAME";
const auth_pw = "YOUR_API_PASSWORD";

var headers = {
    'Content-Type': 'application/json',
    'Authorization': 'Basic ' + new Buffer( auth_un + ':' + auth_pw ).toString('base64')
};

async function createPersonWithNameAndEmail(firstName, lastName, emailAddress)
{
  // First create person, returning id.
  var newPersonId = await callBandWindowAPI(
    {host: api_host,
     path: '/dg3_rpchost/Zealand/crm/DataAPI/PersonDAL/create_restapi',
     method: 'POST',
     headers: headers},
    {}
    );

  console.log("New person created: " + newPersonId);

  // Update fields on new person to add a first and last name. Will only update fields we specify in JSON object below!
  await callBandWindowAPI(
    {host: api_host,
     path: '/dg3_rpchost/Zealand/crm/DataAPI/Fields/FieldsDAL/update',
     method: 'POST',
     headers: headers},
    
     // data sent: Can be used to set any field, provided format is correct.
     // To get the field name to use for any, field:
     // 1. Go into a person card
     // 2. Click "Organise"
     // 3. Double-click on the field of interest.
     // 4. To the right of "Personalisation" is the name of the field to use.
    {person_id: newPersonId,
     data: {firstname: firstName,
            lastname: lastName}
     }
    
    );

   // Add an e-mail address for this person.
   await callBandWindowAPI(
    {host: api_host,
     path: '/dg3_rpchost/Zealand/crm/DataAPI/ContactDAL/create',
     method: 'POST',
     headers: headers},
    
    // data:
    {person_id: newPersonId,
     contact: {type: "email", subtype: null, valid: true, active: true, value: emailAddress}
    
    });
}

createPersonWithNameAndEmail("Douglas", "Engelbart", "[email protected]");

James,
Here's a tip:
Always send a JSON body in your POST, even if you have nothing to send. You can just send "{}" in that case.