send_job_alert_email.js

export function sendJobAlertEmail() {
  console.log('CRON: sending alert email');

  function handleJobs(jobs, user, notifiableJobs, done) {
    each(jobs, (job, n) => {
      Notification.count({ jobId: job._id, userId: user._id }, (err, count) => {
        if (count > 0) {
          console.log('notificaiton already sent');
          return n();
        }
        console.log('job found', job.title);
        notifiableJobs.push(job);
        n();
      });
    }, done);
  }

  function handleCompanyIds(companyIds, user, notifiableJobs, done) {
    each(companyIds, (companyId, n) => {
      Job.find({ company: new ObjectId(companyId) }).populate('company').exec((err, jobs) => {
        console.log('job count', jobs.length);
        handleJobs(jobs, user, notifiableJobs, n);
      });
    }, done);
  }

  function handleFollowings(followings, done) {
    each(followings, (following, n) => {
      const notifiableJobs = [];

      User.findById(following.userId, (err, user) => {
        if (!user.emailVerified) {
          console.log('email not verified');
          return n();
        }

        handleCompanyIds(following.companyIds, user, notifiableJobs, () => {
          if (notifiableJobs.length === 0) {
            console.log('No jobs to notify');
            return n();
          }

          const mailOptions = buildEmail({ jobs: notifiableJobs, user });
          sendEmail(mailOptions, (err) => {
            if (err) {
              console.log('Error while sending job email', err);
              return;
            }

            each(notifiableJobs, (notifiedJob, m) => {
              let doc = new Notification({ jobId: notifiedJob._id, userId: user._id });
              doc.save(m);
            }, n);
          });
        });
      });
    }, done);
  }

  waterfall([
    (cb) => {
      Following.find({}, cb);
    },
    handleFollowings
  ], (err) => {
    if (err) {
      console.log('Error while sending job email', err);
    }
    console.log('done');
  });
}