[heijmans]

You don't have to be an expert in TypeScript to know that the TypeScript compiler just strips the types from the code and leaves the rest as-is (if you are targeting a somewhat modern JS engine). The runtime performance of a TypeScript program is the same as that of the equivalent JavaScript program.

But of course, a TypeScript program could be much slower than a different JavaScript program, as is probably happening in this case.

I agree with others that the difference in results between JavaScript and TypeScript makes the quality of this paper highly suspect.

[benj111]

Well you need to know enough to know whether it's doing run time checks also.

And also whether it's generating less efficient code to satisfy the type safety requirement.

[Thiez]

It isn't. Typescript is basically javascript with type annotations. There is a shorthand for class member initialisation and for defining enums, but that's basically it. There are no extra safety checks inserted. You get compile-time typechecking and nothing else.