I'm writing a Windows 8.1 HTML5/Javascript store app and posts about this refer to using source map files in a supported browser. Just curious if anyone has gotten this working seamlessly by placing a breakpoint in their .ts file in Visual Studio.
1 Answer
Windows 8.1 project
If you are facing issues with debugging TypeScript in Win8.1, I'd suggest to download and run sample/working project first. E.g. Encyclopaedia works for me, see:

The trick is in JavaScript mapping files. So, if this works for you, copy important parts from Encyclopedia.jsproj (like TypeScriptSourceMap at the very end of file and Import of TypeScript .targets) to your jsproj. Hope this helps.
Web project
To debug JavaScript or TypeScript run your application using an Internet Explorer:
In Standard toolbar change a Debug target to IE

Navigate to your .ts file and place the breakpoint
Press the green arrow :o)
If it still doesn't work, install the Web Essentials extension.
I have it tested also with Chrome and FF, but it doesn't work.
debugger;command to get things to stop where you want.