FOLLOW THIS QUESTION TO RECEIVE UPDATES
The job market as a whole is shifting toward Node and React and away from Angular 1.x and Rails. Many of the major Silicon Valley companies such as Facebook, Instagram, Uber and AirBnB use React and will be around for a long time. For a more complete list of companies using React, check here: https://github.com/facebook/react/wiki/Sites-Using-React.
This is not to suggest other stacks are not good for your career. There is still plenty of Rails and Angular work to be found. The question is, where do you sit relative to the labor pool for Rails and Angular? Almost every bootcamp in the US teaches Rails and Angular has been around for five years. In order for you - a beginner - to be competitive in that market, you will need several years of training to catch up.
Conversely, React is still new (about two years) and also high in demand. This is the sweet spot you want to be in - just like iOS was in 2009. So as an entry level dev, you will have less competition and will be more desirable to start. You can read a much more in depth analysis here: https://www.velocity360.io/post/starting-out-today.
One thing I tell potential students is to go to one of the various job search sites like Career Builder and put in their zip code and search for different technologies. See how many jobs are listed in YOUR area for each technology. You'd be surprised at how regional some of these things can be.
I agree with Dan that long term you will have to shoot ahead of the curve to pick the technology that will be common later, but since you are going the bootcamp route, you also have to be mindful of what's in demand now. Since bootcamps are short, you want to make sure you don't shoot too far ahead at first.
The next thing you need to consider is whether you want to work for start-ups or established companies. Both can be great careers, but the advice I give is different for each. Dan's advice is geared towards the start-ups and one reason why I teach Node myself. If you'd rather work for an established company in a more "corporate" job, then I'd recommend either Java or Microsoft's .Net. That's why I also teach .Net.
As a beginner I think you should play the numbers and angle towards the most plentiful tech in your area. It's simple arthimetic that you have a greater chance of landing one of 100 jobs rather than one of 10. In my area (Atlanta) that's the basic ratio you'll find between corporate and start-up jobs. In a smaller market you might shift the decimal point down on both numbers.
Of course you have to figure out for you which is the better fit. Some people are only happy working in a start-up and some people are only happy working in a corporate job.
Hope this helps!
Code Career Academy (http://codecareeracademy.com)
The discussion of the stack and language is a red herring. You select this specific service by results. In most cases that result is a JOB. Once you have a JOB you can jump from stack to stack at will, if you want.
Once you have transition into a job as a software developer you will have a much better perspective on everything else that people might want to talk to you about.
Here is a guide to help you flesh out the real important stuff and identify the camps trying to push silly stuff: