Ask HN: What technologies did you learn in 2018?

New top story on Hacker News: Ask HN: What technologies did you learn in 2018? What technologies have you invested time in learning that you are going to keep using/experimenting/learning about in the next year? I'm a professional Android engineer, and as for me: I learned Kotlin and use it at work every day, and so far I like it a lot. I also learned a little bit of iOS development with Swift. I also experimented with Flutter developing non-trivial "Hello world" apps, and I feel that it reduces a lot of friction that a lot of native mobile developers encounter. What's your favorite tech in 2018?