Node service responsible for generating and sending the email verification email and for verifying the link

EmailVerificationService.js

const _ = require('lodash');

class EmailVerificationService {

    constructor(server) {
        this.server = server;
        this.logger = server.plugins.core.LoggerService.tagged('EmailVerificationService');
        this.jwtKey = server.app.config.get('/jwt/key');
        this.MailService = server.plugins.mail.MailService;
        this.MailTemplateService = server.plugins.mail.MailTemplateService;
        this.JWTService = server.plugins.core.JWTService;
    }

    static init(...args) {
        if (this.instance) return this.instance;
        this.instance = new this(...args);
        return this.instance;
    }

    verify(hash) {
        return Promise.resolve()
        .then(() => this.JWTService.decode(hash))
        .then((email) => {
            if (!email) {
                throw new Error(`Unable to retrieve email from hash ${hash}`);
            }

            return this.server.plugins.users.User.findOne({ where: { email } })
            .then((user) => {
                if (!user) {
                    throw new Error(`Unable to retrieve user by email ${email}`);
                }
                return user;
            })
        })
        .catch((err) => {
            this.logger.error(err);
            throw new Error('Invalid email verification code');
        });
    }

    getVerificationLink(email) {

        return Promise.resolve()
        .then(() => {
            return this.JWTService.encode(email)
            .then((hash) => {
                if (!_.isString(hash)) {
                    throw new Error(`getEmailVerificationLink expects String hash, got: ${typeof hash} ${hash}`);
                }
                const path = `/verify-email?h=${hash}`;
                const hostname = this.server.app.config.get('/app/hostname');

                return `${hostname}${path}`;
            });
        });

    }

    sendVerificationEmail(email) {
        return this.getVerificationLink(email)
        .then((emailVerificationLink) => {
            const tplParams = { emailVerificationLink };

            const html = this.MailTemplateService.getCompiledTemplate('verifyEmail', tplParams);

            return this.MailService.send({
                to: email,
                subject: 'Verify account email',
                html
            });
        })
    }

}

module.exports = EmailVerificationService;