No Typescript compilation errors

If I write Typescript that would otherwise suffer from a compilation error, Web Maker gives me no alerts or indication that what I've written isn't valid Typescript.

`const WebMakerVersion: number;
WebMakerVersion = "compliation error";
document.write(WebMakerVersion)`

This should throw a compilation error; WebMakerVersion cannot be assigned a string, and it can't be assigned; it should be initialized when it is declared. But I don't see anything.