Introduction

Either you love it or hate it, but in the age of Microservice and REST API, you can not ignore Javascript. Javascript was once upon a time used only in client-side (browser), but node js (execution engine/run time/webserver) make it possible to run Javascript on the server-side. Javascript is everywhere, on Desktop/Server/Mobile. You can create mobile web apps with javascript and html5, which has a lot of advantages.

Introduction

You can save the $99 yearly licensing cost to pay Apple for making IOS apps. You don't have to purchase a MAC laptop to make your IOS app(Apple's apps can only be made in MAC), you are not dependent on Apple's mercy to follow its guideline for making apps and Apple is infamous for rejecting the apps for its store.
Javascript stormed web technology, and nowadays, from small software shops to fortune 500 companies, everyone is using node js for web apps. Recently wordpress.com rewrote its dashboard in Javascript, PayPal also rewrote some of its components in Javascript.
However Javascript is quirky/dynamic/scripting/ functional oriented language, and it has its own idiosyncracies.
It is not scalable, it is good for some 3000 lines of code but for big apps, you can't manage it, read it properly, or debug it.
So HOW TO BE JAVASCRIPT DEV WITHOUT DOING JAVASCRIPT:
Some smart developers/companies make compilers/transpilers which convert your OTHER language code into javascript code.(BEST OF BOTH WORLDS)
C++:
If you know C++, then it is possible.
Cheerp compiler:
It is free for opensource commercial projects as well as for closed source non-commercial projects.
JAVA:
GWT(google web toolkit 88000 lines of code) compiles Java to Javascript.
JSWEET:
IT IS A SYNTAX WRAPPER, WHICH CONVERTS JAVA TO TYPESCRIPT TO JAVASCRIPT.
KOTLIN:
Kotlin is a very promising language, which runs on Android, JVM, and on browser/nodejs.
Main thing is, Kotlin language is not made by Academia or Research Labs (like C/C++/PYTHON/SCALA Languages), but it is made by a professional company, which makes Developer's Tools(https://www.jetbrains.com/).
SCALA:
A mix of the object-oriented and functional approach. It is a static language, but can be used as a dynamic language.
TWITTER/LINKEDIN and many big enterprise apps are written in SCALA language. so you write code in S and it gets compiled/transpired into Javascript.
C#:
Beautiful and most productive language. You can write your code in C# and convert it into Javascript.
http://bridge.net/
TYPESCRIPT:
BRAINCHILD OF Anders Hejlsberg, who made Turbo Pascal, Delphi, C# language. TypeScript lets you write JavaScript the way you really want to. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. Any browser. Any host. Any OS. Open Source.