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twooster | 4 years ago

I've seen this take so many times an I simply don't get it. The notion that TypeScript can't be (some form of) strongly-typed because Javascript is (some form of) weakly-typed is just silly. CPUs are entirely weakly typed in this sense and this doesn't impact the typings of languages built on top.

JavaScript is strongly typed in the sense that every value has a well-defined type. It's weak in the sense that it has implicit conversion between types in a lot of cases, but it's not as though those conversions don't follow particular rules if you know the types.

TypeScript gives you accurate static typing on top of that, so long as you don't use `any` as an escape. Arguably, `JSON.parse` returning `any` is the 1-million dollar mistake of TypeScript, because it leads a lot of people to think that they get automatic runtime typechecking for free, which they obviously don't, which leads to comments about how bad/slippery TypeScript is stemming from their misunderstanding.

In my experience, you only need to work around typings in TypeScript when you're dealing with some absurdly designed API that only made sense in the super-flexible world of olden-days JavaScript, or perhaps if you're doing some meta-programming, generating class definitions on the fly or such.

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andrew_|4 years ago

> I've seen this take so many times an I simply don't get it.

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.

twooster|4 years ago

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.

wruza|4 years ago

The definition of a strongly typed language has been well-cemented for some time

What is it? Is e.g. C++ strongly typed in that sense?