Typescript is a type safe language that "compiles" into javascript. The Microsoft implementation compiles on save, so you work in your file.ts and a program running somewhere fires when the file is saved and converts it to file.js which you would distribute.

I haven't used it yet, but the demo from Anders looked good. It's an attempt to fix the "loosey goosey" nature of javascript. I would be great if browsers supported it as a built in language.

https://channel9.msdn.com/posts/Anders-Hejlsberg-Introducing...

If you watch the video, you'll notice the argument notation is name: type rather than type name. I think Anders is reminiscing about his Delphi days.