Yes, it's still a transpiler, I'm not saying it isn't, but what I mean is that it doesn't add any functionally specific to the typescript language. There's a transpiler for TS that doesn't even do any type checking at all and just does the type stripping and back porting. But of course, that's not why people use typescript. All the features that are actually important to typescript could be done through a linter instead. If type annotations were added to JavaScript you could get most of typescript's features with linting rules and just handle back porting in a more standard way.