JavaScript itself + Web APIs + at least basics of CS, Software Engineering and Software Architecture. Period.
When you know that, you will be able to <s>write your own from scratch</s> learn anything very fast and be much more valuable and expensive talent for general purpose. Good companies hire software engineers and not Angular coders. At the end you will have to adapt to any job every time.
Don't seek for popularity or hype, seek for self improvement, how to learn faster, how to solve problems, most important skill - how to think, and ask yourself Why 100 times a day. Trust only your own experience and results.
Don't think, research. Software Engineering is about 100% correct answer and nothing else. 99.99% is no. You can just compare numbers for different searches/keywords across different platforms for your market. (Welcome to the basics of statistics and data science as well)