React is mature and robust now, and still growing in popularity like a rocket. It's not going to be gone tomorrow. Angular 2 is just starting to become stable, but it still uses some ideas pioneered in Angular 1 going on 4 years ago.

It also won't be gone tomorrow. Angular is still the dominant framework by a healthy margin. Yeah, there are newcomers like Vue.js, but they're currently about 1/10th as popular as React.

This "over in 5 minutes" meme in the JS discussions isn't exactly telling the whole story.