pal-jius-case-study-mailchimp-schmervice.js

'use strict';

const Hoek = require('@hapi/hoek');
const Wreck = require('@hapi/wreck');
const Schmervice = require('schmervice');

module.exports = class MailchimpService extends Schmervice.Service {

    constructor(server, options) {

        super(server, options);

        const {
            apiKey,
            baseUrl,
            listId
        } = options.mailchimp || {};

        Hoek.assert(apiKey && baseUrl && listId, 'Must specify options.mailchimp.apiKey, options.mailchimp.baseUrl, and options.mailchimp.listId');

        this.apiKey = apiKey;
        this.baseUrl = baseUrl; // Ex: 'https://us20.api.mailchimp.com/3.0'
        this.listId = listId;
    }

    async subscribe(newUsers) {

        // Here's where it's really nice having schmervices with nicely-cut concerns to compose together!
        const { logService: { log } } = this.server.services();
      
        // See the Mailchimp docs to better understand what's happening here: https://mailchimp.com/developer/reference/lists/#post_/lists/-list_id-
        const rawResult = await Wreck.request('POST', `${this.baseUrl}/lists/${this.listId}`, {
            headers: {
                Authorization: `apikey ${this.apiKey}`
            },
            payload: {
                members: [].concat(newUsers).map(({ email }) => ({
                    email_address: email,
                    status: 'subscribed'
                })),
                update_existing: true
            }
        });

        const readResult = await Wreck.read(rawResult);

        const res = JSON.parse(readResult.toString('utf8'));

        const updates = {
            new: res.new_members.map(({ email_address }) => email_address),
            updated: res.updated_members.map(({ email_address }) => email_address)
        };

        log(['mailchimp', updates.new.length ? 'signup' : 'update'], updates);

        return updates;
    }
};