In typescript, the type of 'file' implicitly changes, which is more information to keep track of. In the rust example, a new variable is explicitly introduced—

In typescript, the type of 'file' implicitly changes, which is more information to keep track of. In the rust example, a new variable is explicitly introduced—though, granted, it shadows the old by using the same name—and every variable has a static type for the entirety of its lifetime. Which being said, I don't have a preference for either of those styles.