JS can now be used on the server (with Node), on mobile (with ReactNative / Ionic / etc), on the embedded (with CylonJS). Do you think there will be one language in the future which will make lives of dev's a lot easier?
There will never be one language, and honestly, learning languages is never really the bottleneck anyways (rather learning the domain and applicable libraries are). A single language to rule them all might boost industry productivity by .1 or .2%, maybe, but I doubt it.
That's an absolute fantasy that JavaScript will be the one language that will be used as a single option in the future.
Not even taking into account that often languages and frameworks are chosen on the basis of the problem you are solving (and you just happen to work in the field where JS is more popular/viable choice) - it is extremely poorly designed language (and probably only PHP is worse at this) and I always question the sanity of the people that choose to use it on server-side (but there are good reasons to use it there - they are just rare).
JavaScript is plagued with problems like: - No static typing support by default - Before ES6 the class support was a mess - No Standard Library! - NPM and the whole dependency system is hell
There is a reason why people keep writing languages like Dart, Elm, CoffeeScript, and TypeScript.
TypeScript and Dart deserve some special attention - the problems with JS were (and still are) so big and annoying that big companies like Google and Microsoft spend thousands of man-hours developing things like Static-typing support, Standard Libraries, and, most importantly, tooling.
And we haven't yet scratched the "real enterprise systems" where transactionally support is a must. JavaScript has yet to go through so much shit to develop frameworks like JMS, Hibernate, and Spring that enable you to do all the fancy transactional stuff just with annotations. However, I do not see anybody developing something like JavaScriptSpring because JS fundamentals are broken and nobody will build big software in such a language because it is just not feasible.
I guess that's enough for now - it's already too ranty.
And you forgot on your list that JS makes your SmartTV, STB, Xbox, PS, Wii, and many more platforms work. An example, Netflix for all those platforms is made with JS. You've also got react native and Cordova for mobile.
The future is either JS or very specific systems languages (C/C++/Rust).
Web assembly may level the playing fields for other languages eventually but it will probably be too late, so javascript will continue to be the native imperative browser language and, in as much as developers care about "one imperative language everywhere" it will be the most obvious option.
My effort (intercooler.js) is to use HTML as the main client side language: it's native and declarative, and lets you take advantage of REST/HATEOAS naturally in a way javascript SPA frameworks don't. By minimizing client side javascript, and since you are always going to be dealing with HTML anyway on the web, you can pick whatever backend technology you like (I like rails) without adding in a new language to the cognitive load of your app.
Meanwhile...next to nobody uses Clojurescript.
Give me ONE great example. Angular/2/4 is crappy and can't stand against React, much less Reagent/Om (cljs).
Did you already use typescript? Because that is a really shit tech. Thanks god I don't have to use Enterprise bullshitness to sell software.
Some days, I like to imagine a world where browsers had Python embedded as their scripting language.