Where does TypeScript define functions provided by the JavaScript language itself?

TypeScript is a great choice for all your (web) application that need JavaScript. TypeScript provides also nice support inside Visual Studio, for instance you have full IntelliSense support, including member and parameter insights.

TypeScript code is automatically translated into JavaScript, and all JavaScript code is also valid TypeScript code. But where does TypeScript find the definitions for the JavaScript language itself? The answer is in this definition file:

C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\
CommonExtensions\Microsoft\TypeScript\lib.d.ts

The file is about half a megabyte in size, so the amount of script definitions is substantial.

Hope this helps!