AWS Lambda function for Mailchimp list subscription

.env

API_KEY='xxxxxxxxxxxxxxxxxxx-us1'
LIST_ID=12033101ax

index.js

require('dotenv').load();

var Mailchimp = require('mailchimp-api-v3');

// mailchimp environment variables
var API_KEY  = process.env.API_KEY,
    LIST_ID  = process.env.LIST_ID;

// function for subscribing a user
function addToList(emailAddress) {
  var mailchimp = new Mailchimp(API_KEY);
  mailchimp.request({
    method : 'post',
    path : '/lists/' + LIST_ID + '/members',
    body : {
      email_address : emailAddress,
      status : 'subscribed'
    }
  }).then(function(results) {
    console.log(results);
  })
  .catch(function (err) {
    console.log(err);
  });
}

exports.handler = function(event, context, callback) {
  var emailAddress = event.email;
  console.log(event.email);
  addToList(emailAddress);
}

package.json

{
  "name": "mailchimp-lambda-subscription",
  "version": "1.0.0",
  "description": "A Lambda function to create a subscription to a Mailchimp List",
  "main": "index.js",
  "scripts": {
    "zip": "zip -r mailchimp-lambda.zip .env index.js node_modules/"
  },
  "author": "Luke Duncan",
  "license": "MIT",
  "dependencies": {
    "mailchimp-api-v3": "*"
  },
  "repository": {
    "type": "git"
  }
}