notify.js

  const mailgun = require('mailgun-js')({apiKey: api_key, domain: domain});
  const twilio = new require('twilio')(accountSid, authToken);

  export default function notify (to, msg, options) {
    if (Array.isArray(to)) {
      to.forEach((toSingle) => notify(toSingle, msg, options));
      return;
    }

    if (to.includes("@")) {
      mailgun.messages().send({
        from: 'Your name <yourname@example.com>', // your email
        to: to,
        subject: options && options.subject,
        text: msg
      });
    } else {
      twilio.messages.create({
          body: msg,
          to: to,
          from: '+5555555555' // your number
      });
    }
  }