Some background on how JavaScript got cool
Before coming to Dev Bootcamp, I had worked with JavaScript and its related web frameworks for a year or so.
I had focused my independent study on JavaScript leading up to Dev Bootcamp after learning about several advances in the JS community that I found very intriguing. Underlying these advances is the basic acknowledgement that JavaScript is everywhere. Although JavaScript was not originally used to create web apps, it is the most widespread programming language used on the web because of the interactive dynamics it can add to an otherwies static web page.
Some very smart people recognized that JavaScript is such a flexible language that it could do much more. Paul Buchheit, for example, was working at Google when he was charged with creating an email application for Google around the year 2000, and he found JavaScript's highly interactive nature capable of creating a desktop application type of interface within a web page. About five years later, JavaScript was released to the public.1 Not only did gmail become one of the world's most dominant email applications, but this pioneering application unequivically demonstrated JavaScript's tremendous capacity to operate as a programming language unto itself. Since Node.js was released in 2009, it has brought such robust app building capabilities to the server as well.
In this light, JavaScript frameworks like React.js and Meteor.js have been designed to operate on the server as well as the client.
Ruby has an edge, but that may be diminishing
In my basic level of understanding, Ruby still has an edge over JavaScript in its intuitive syntax, implementation of Object Orientation, and undoubtedly more ways that I haven't learned about yet. JavaScript was first developed to compliment Java, and it was not originally intended for more complex use. 2 Ruby was developed at around the same time with Object Orientation as the main goal. 3
The good news for JavaScript is that some of those smart pepole who recognize JavaScript's potential have decided to improve it. I don't know enough about programming in general to wrap my head around all the changes being made, but EcmaScript2015 is the latest release of JavaScript implementation standards, and they reportedly put a date on it becuase they plan to release another one fairly soon afterwards. So, as effective as JavaScript is, it apparently is going to get better.