Integration between MailChimp and React Native app

Everything quiet around here? In the middle of some researches and thoughts, I had a possible idea to solve this problem, here is what I did to integrate MailChimp and Firebase into a React Native Application:

First of all, I did some research, and realized that the best way to do this would be for the server side, since I was already using the Firebase Realtime Database, so I decided to use the Cloud Functions to solve this problem. creating a Cloud Function, which is checking the state of the Database, and when a data is received, a POST is triggered for the MailChimp API, below the function created for this:

const functions = require('firebase-functions');

\Code suppressed here

exports.onDataAdded = functions.database.ref('/xxx/{id}').onCreate((snap, context) => {
    const data = snap.val();
    var fetch = require('isomorphic-fetch');
    var btoa = require('btoa');

    console.log(data.email);
    // POST /lists/{list_id}/members
    // Add a new list member

    var MAILCHIMP_API_KEY = 'Key Here';
    var listId = 'Id Here';
    // NOTE: mailchimp's API uri differs depending on your location. us6 is the east coast. 
    var url = 'https://<dc>.api.mailchimp.com/3.0/lists/' + listId + '/members';
    var method = 'POST';
    var headers = {
        'authorization': "Basic " + btoa('randomstring:' + MAILCHIMP_API_KEY),
        'Accept': 'application/json',
        'Content-Type': 'application/json'
    };
    var body = JSON.stringify(
        {
            email_address: data.email,
            status: 'subscribed',
            'language': data.language,
            merge_fields: { FNAME: data.name }
        }
    );

    return fetch(url, {
        method,
        headers,
        body
    }).then(resp => resp.json())
        .then(resp => {
            return console.log(resp)
        })
        .catch(error => {
            throw new Error(error.statusText)
        });
});

With this function created in the Firebase Cloud Functions, as soon as some Realtime Database insert is performed, this trigger triggers this function.

Thanks for the quick answers !!

Follow the code that performs this integration from node.js and axios

const axios = require('axios')

const mailchimpOptions = {
  apiKey: 'xxxxxxxxxxxxxxx',
  listId: 'xxxxxxxxxxxxxxxxx',
}

const axiosInstance = axios.create({
  auth: {
    username: 'anystring',
    password: mailchimpOptions.apiKey,
  },
})

function subscribe(req, res) {
  axiosInstance.post('https://us15.api.mailchimp.com/3.0/lists/${mailchimpOptions.listId}/members', {
    email_address: req.body.email_address,
    status: 'subscribed',
  }).then((response) => {
    if (response.data.status === 'subscribed') {
      res.send({
        success: true,
        message: 'Obrigado! Estamos direcionando seu contato para nossos consultores.',
      })
    } else {
      res.send({
        success: false,
        message: 'Parece que você já está cadastrado. Outros assuntos mande um e-mail para xxxxxxxx',
      })
    }
  }).catch((err) => {
    if (err.response.data.title === 'Member exists') {
      res.send(400, {
        success: false,
        message: 'Obrigado pelo interesse! Seu contato já está cadastrado.',
      })
    } else {
      res.send({
        success: false,
        message: 'Parece que você já está cadastrado. Outros assuntos mande um e-mail para xxxxxxxx',
      })
    }
  })
}

module.exports = subscribe