mail-subscription-service/register_subscriber.js

const chalk = require('chalk')
var Subscriber = require('./models/subscriber');

var register_subscriber = function(data) {
    return new Promise((resolve, reject) => {
        if(data.email == '' || data.email == undefined || !validateEmail(data.email)) {
            console.log(`${chalk.red(`Error: Received data does not contain a valid email address`)}`);
            console.log(data);
            resolve(undefined);
        }
        Subscriber.findOne({email: data.email}).then((subscriber) => {
            if(subscriber != undefined) {
                subscriber.attempted_registration();
                subscriber.save().then((subscriber) => {
                    console.log(`Subscriber already in list ${chalk.italic(`\'${subscriber.email}\'`)}`, );
                    var payload = response_payload(subscriber, true);
                    resolve(payload);
                }).catch((error) => { reject(error); });
                
            } else {
                var new_subscriber = new Subscriber(data);
                new_subscriber.save().then((subscriber) => {
                    console.log(`Registered new subscriber ${chalk.italic(`\'${subscriber.email}\'`)}`);
                    var payload = response_payload(subscriber, false);
                    resolve(payload);
                }).catch((error) => { reject(error); });
            }
        }).catch((error) => { reject(error); });
    });
}

var response_payload = function(subscriber, registered) {
    var payload = {};
    if(subscriber != undefined) {
        payload.email = subscriber.email;
        payload.first_name = subscriber.first_name;
        payload.last_name = subscriber.last_name;
        payload.registration_attempts = subscriber.registration_attempts;
        payload.registration_date = subscriber.registration_date;
        payload.last_updated = subscriber.last_updated;
        payload.confirmed_subscription = subscriber.confirmed_subscription;
    } else payload.confirmed_subscription = false;
    payload.already_registered = registered;
    return payload;
}

var validateEmail = function(email) {
    const re = /^(([^<>()[\]\.,;:\s@\"]+(\.[^<>()[\]\.,;:\s@\"]+)*)|(\".+\"))@(([^<>()[\]\.,;:\s@\"]+\.)+[^<>()[\]\.,;:\s@\"]{2,})$/i;
    return re.test(String(email).toLowerCase());
}

module.exports = register_subscriber;