Learned modeling for Machine Learning. Took Andrew Ng's ML course then Coursera's Deep Learning specialization. I already had a data science background, doing NLP data collection, processing, and building annotation tools (for text, images, audio, and video) at my day job (Ruby on Rails mostly). I did have to do a lot of brushing up on long-neglected math skills (Khan Academy is amazing!) and continue to do so.

Also took a React course and have been building my own project with React and Redux.

Just spent this morning reading up on GraphQL... by the end of the day I expect I'll have finished reading the "Learn" pages and some documentation and have worked with it a bit.