[visual-studio] Where can I find the TypeScript version installed in Visual Studio?

The TypeScript team sorted this out in Visual Studio 2017 versions 15.3 and later, including the free Community edition.

How to See Which TypeScript Versions are Installed in Visual Studio

All you now need do is to go to project properties of any TypeScript Visual Studio project (right-click the project file in Solution Explorer/Properties), then go to the TypeScript Build tab on the left-hand side. This has a 'Typescript version' dropdown that shows you the version the project is using, and if you open it the dropdown shows you ALL versions of TypeScript currently installed in Visual Studio.

The actual installs are currently at C:\Program Files (x86)\Microsoft SDKs\TypeScript and then subfolders by version number, at least on Win10 on my computer. If you want to see the exact version (e.g. 2.8.3 rather than just 2.8) you can find the appropriate tsc.exe in here and look at its properties (Details tab in right-click/Properties in File Explorer).

How to Install Specific TypeScript Version

If you want to install a specific version of TypeScript for Visual Studio, you can download older versions from the Details->Releases section of the TypeScript SDK for Visual Studio 2017 Downloads page. You can verify that the version has been installed either with the 'Typescript version' dropdown in VS or inspecting the C:\Program Files (x86)\Microsoft SDKs\TypeScript folder.