[BigJono]

I've never used Typescript, but I don't think these are really 'major' flaws. That's just my perspective as someone that's being doing FE for over a decade and picks this stuff up fairly quick. Obviously it's more of a problem for newbs that probably aren't going to read that paragraph about discriminated unions and grok it straight away.

Having said that, I absolutely hate the ending of this blog post. I see blog writers do this all the time. He's just given three detailed, concrete negatives about Typescript, given enough information to infer that these quirks could be problematic for beginners and cost your team time and resources. Then at the end, he suggests that you use Typescript and waves it all away with some ambiguous bullshit about how static typing saves you a bunch of time.

There's so many of these claims that are just taken as common knowledge/best practices, that everyone treats as absolute truth that overrules everything else, even good concrete examples. I've been building entire apps myself for over a decade now, using both plain and typed (flow) JS, and every time I've seen somebody try and elaborate on how static typing saves you all this time, it's some pissant todo list bug that I would have solved in 5 seconds with plain JS.

[tristanstcyr]

Try working with a large 5 year old JS codebase that's been hammered on by dozens of devs. The problems are no longer just pin point bugs but a systemic lack of modeling.

Static typing is not that much about preventing bugs but more about forcing the code to operate over a well defined model.

Can you write good code without static typing? Yes. Can you scale and maintain it in a large organization, probably not.