Josh's content is always very very high quality. I look forward to him releasing his online React course [0] so that I can recommend it to others who are starting out.
My personal biggest not-total-comprehension is around Hooks / effects. I've followed tutorials, used them in production, etc. I'm comfortable using them but I also consider them a bit of a black box, which I don't like (e.g. I'm not sure how they're implemented). The other (even bigger) question for me is "why" -- what prompted the React team to change everything over to "effects". Anyone?
My personal biggest not-total-comprehension is around Hooks / effects. I've followed tutorials, used them in production, etc. I'm comfortable using them but I also consider them a bit of a black box, which I don't like (e.g. I'm not sure how they're implemented). The other (even bigger) question for me is "why" -- what prompted the React team to change everything over to "effects". Anyone?
[0] https://www.joyofreact.com/