http://www.unixgeeks.org/security/newbie/unix/cron-1.html – unix cron man pages https://github.com/ncb000gt/node-cron – node-cron github

var CronJob = require('cron').CronJob

try {
  new CronJob('00 15 6,18 * * 0-6', () => {
    console.log('hello there!', new Date().toLocaleTimeString())
  }, null, true, 'America/Chicago')
} catch(ex) {
  console.log('the pattern was not valid!')
  console.log(ex)
}

This Cron job will run everyday of the week, twice a day at 6:15am and 6:15pm because of the argument '00 15 6,18 * * 0-6'. Checkout the docs to learn more about setting the times for the Cron job.