Is React Just a Fad?

I am just learning how to code and I think I have a decent grasp on things but do not think I could hold a job yet. I am intermediate in HTML, CSS, Swift but Javascript just passing knowledge.

Do I need to know JavaScript at a high level before diving head first into React? Is React just the flavor of the day and not worth the time? I heard some pretty big players are using it so I am thinking most answers will be no it's here to stay but I would like to get all your opinions!

Thanks!