If you are getting started with TypeScript just like me, I highly recommend doing the online course by Stephen Grinder on Udemy.
Especially his course: "Typescript: The Complete Developer's Guide".
I myself do a lot of learning online but never have I enjoyed an online course and instructor that much, really the instructor is very good.
Stephen Grinder does a fantastic job explaining all the details and he structures the lessons in a way that is simply not boring at all. He is passionate and can transport that to you, the learner.
Stephen also intentionally repeats very important concepts during the whole course, in my opinion that really helps you learn and understand the concepts in a guided way. All that without really the need for making a whole bunch of notes and doing a lot more research afterwards. It really gets to the point.
"Typescript: The Complete Developer's Guide is indeed a Complete Developer's Guide to TypeScript and deserves that title.
I will certainly lookout for more courses by Stephen Grinder.
Tip: You can get a huge discount if you search for Udemy coupons on the internet and save like 80%.
Side Note: this recommendation is my own, I have no relation to Udemy or the Instructor.