> C++ is just a layer on top of C
C++ used to be just a layer on top of C, but not anymore. If it still was, it wouldn't be a bad thing to say.
Type checks that run during compilation/transpilation/typechecking do not "run" as the code is executed. This is what happens with Typescript, and that's what the original commenter was saying.
"It's just a type checker for JavaScript" - not really. It's a language that transpiles to JavaScript and it happens to be a superset of JavaScript (namespaces and enums, anyone?).
But saying that it's just a layer on top of JavaScript sounds like saying C++ is just a layer on top of C.