TypeScript was used as an example of a well-known language that currently is transpiled to JavaScript. I am not saying that TypeScript will surely be compiled to WebAssembly, just that it could.
TypeScript is designed for development of large applications. It is a superset of JavaScript both because this facilitates learning, but also because there was really not an alternative. In the end you had to compile to JavaScript. It is not hard to imagine a language with the same objective of TypeScript that is compiled to WebAssembly. Furthermore, if TypeScript was compiled to WebAssembly you could use it wherever there was a platform for the WebAssembly format. So if somebody created a project to consume WASM binary files and execute them from within .NET assemblies[1], you could use TypeScript outside the browser and node.
[1] https://www.hanselman.com/blog/NETAndWebAssemblyIsThisTheFut...