SendGrid setup

Mailer.js

const sendgrid = require('sendgrid');
const helper = sendgrid.mail; //don't want to use es6 destructuring b.c we want to call it helper. not mail.
const keys = require('../config/keys');

class Mailer extends helper.Mail {
  //constructor doesnt need to receive a survey model obj.
  //It just has to be an object that has a subject and recipients.
  //the second parameter is the html string, that we'll call content
  //this design lets us use this Mailer for sending more than just surveys
  //this mailer obj is defined here created in the surveyRoutes to send the emails.
  constructor({ subject, recipients }, content) {
    super(); //first runs constructor for Mail class
    //most of the setup here is dictated by sendgrid
    this.sgApi = sendgrid(keys.sendGridKey);
    this.from_email = new helper.Email('[email protected]');
    this.subject = subject;
    this.body = new helper.Content('text/html', content);
    this.recipients = this.formatAddresses(recipients);

    this.addContent(this.body); //Mail class function required to actually register the body.
    this.addClickTracking(); //We write this
    this.addRecipients(); //We write this
  }

  formatAddresses(recipients) {
    //es6 destructuring requires extra parens if you're doing an arrow function
    return recipients.map(({ email }) => {
      return new helper.Email(email);
    });
  }

  addClickTracking() {
    const trackingSettings = new helper.TrackingSettings();
    const clickTracking = new helper.ClickTracking(true, true);

    trackingSettings.setClickTracking(clickTracking);
    this.addTrackingSettings(trackingSettings);
  }

  addRecipients() {
    const personalize = new helper.Personalization();

    this.recipients.forEach(recipient => {
      personalize.addTo(recipient);
    });
    this.addPersonalization(personalize); //addPersonalization class function;
  }

  async send() {
    console.log('send got called');
    const request = this.sgApi.emptyRequest({
      method: 'POST',
      path: '/v3/mail/send',
      body: this.toJSON()
    });
    const response = this.sgApi.API(request);
    return response;
  }
}

module.exports = Mailer;

surveyRoutes.js

const mongoose = require('mongoose');
const requireLogin = require('../middlewares/requireLogin');
const requireCredits = require('../middlewares/requireCredits');
const Mailer = require('../services/Mailer');
const surveyTemplate = require('../services/emailTemplates/surveyTemplate');

const Survey = mongoose.model('surveys');

module.exports = app => {
  app.post('/api/surveys', requireLogin, requireCredits, (req, res) => {
    //es6 restructuring. Out of req.body, I want to get all of these properties
    //off the body thats added to req. The actual adding logic has to be added in.
    const { title, subject, body, recipients } = req.body;

    //use Survey.js model to represent a new instance of the survey being created
    //stored in memory. Has not been persisted at this point.
    const survey = new Survey({
      // es6 syntax, instead of doing title: title
      title,
      subject,
      body,
      recipients: recipients.split(',').map(email => ({ email })),
      //takes the list of email addresses, split into array, and return an obj
      //with key of email and value of email address. Hs been shortened es6 style
      _user: req.user.id, //this is mongo mongoose generated id
      dateSent: Date.now()
    });

    //place to send the email
    const mailer = new Mailer(survey, surveyTemplate(survey));
    mailer.send();
  });
};