Here I'll take a brief look at two, TypeScript and CoffeeScript.
TypeScript version 0.9 was unwrapped in front of Microsoft's developer community during Microsoft's Build 2013 event by Anders Hejlsberg.
In common with many recent Microsoft initiatives there's a strong lean towards openness, exemplified by the Apache 2 licence and CodePlex-hosted source code. In fact, TypeScript is a preview of what to expect in the upcoming ECMAScript 6 standard.
TypeScript header files add type information to existing libraries. A github-hosted project called DefinitelyTyped already contains an impressive collection of '.ts' definition files covering many popular libraries and frameworks, including jQuery, MongoDB, Node.js and D3.js.
There are IDE plugins for Visual Studio and WebMatrix, plus support for editors such as Sublime Text, Emacs and Vim editors. However, at present only Microsoft's Visual Studio 2012/2013 tool delivers comprehensive support for all TypeScript's features.
CoffeeScript appeared in 2009 when Jeremy Ashkenas placed an early version on GitHub. The stable 1.0 version appeared in December 2010.
To find out more checkout the free open source introduction to CoffeeScript.
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