Javascript

http://urish.org/

https://brendaneich.com/2015/06/from-asm-js-to-webassembly/

Two features of JS make it really special –

1. The ability to extend “built-in” classes like String. You can add a reverse() method to the String class !
Cant imagine doing this in C++ or Java.

2. The ability to define new object properties at run-time. Like objects can take on different forms at runtime depending on context. This makes it extremely flexible.