https://en.wikipedia.org/wiki/Strong_and_weak_typing
Wikipedia disagrees with you in the opening paragraph about strong and weak typing: it's contentious. For all practical purposes that I can think of, TypeScript creates a strongly typed environment.
The problem comes when you're interacting with non-typed (or, worse, incorrectly-manually-typed) libraries, or misuse `any`. Honestly, I'd be interested to see a pure TypeScript program and where weak typing comes in. There are definitely a couple of language escapes (again, `JSON.parse`, previously `fn.bind`), but these are going away as TS gains better inference and type-propagation logic.
That may sincerely be, because how it feels as you're using it doesn't align with the objective truths of how it behaves. The definition of a strongly typed language has been well-cemented for some time. TypeScript does not completely align with that definition, thus it cannot be considered truly strongly typed.