Doing a short JavaScript training for colleagues. What should I teach them?

I am going to do a two hour training for my colleagues in JavaScript and the surrounding ecosystem. They are developers with 2-8 years of experience mostly doing SharePoint projects and websites. Their technology is stuck in 2009, with bare HTML+jQuery. They can do a bit of nodejs too. My plan is to talk about three things: - cool features of ES6/7 like async-await. - webpack basics - vue.js basics What else should I teach them?