Programming

Is there some huge benefit that I’m missing?

For example I recently fixed a bug where a function would return an integer 99.9999% of the time, but the other 0.0001% returned a float. The actual value came from a HTTP request, so it started out as a string and the code was relying on dynamic typing to convert that string to a type that could be operated on with math.

In testing, the code only ever encountered integer values. About two years later, I discovered customer credit cards were charged the wrong amount of money if it was a float value. There was no exception, there was nothing visible in the user interface, it just charged the card the wrong amount.

Thankfully I'm experienced enough to have seen errors like this before - and I had code in place comparing the actual amount charged to the amount on the customer invoice... and that code did throw an exception. But still, it took two years for the first exception to be thrown, and then about a week for me to prioritise the issue, track down the line of code that was broken, and deploy a fix.

In a strongly typed language, my IDE would have flagged the line of code in red as I was typing it, I would've been like "oh... right" and fixed it in two seconds.

Yes — there are times when typing is a bit of a headache and requires extra busywork casting values and such. But that is more than made up for by time saved fixing mistakes as you write code instead of fixing mistakes after they happen in production.

Having said that, I don't use TypeScript, because I think it's only recently become a mature enough to be a good choice... and WASM is so close to being in the same state which will allow me to use even better typed languages. Ones that were designed to be strongly typed from the ground up instead of added to an existing dynamically typed language.

I don't see much point in switching things now, I'll wait for WASM and use Rust or Swift.

Can’t you just use try/catch blocks

No, because what if whatever you're calling is updated and suddenly it throws a new exception where before it didn't? Python or JavaScript or other interpreted languages will never warn you about that.

if the data structure of whatever you’re working with isn’t what you expected?

That sounds like a whole lot of boilerplate I have to write to verify every time that something is what I expect. Static typing does that for me much easier and more reliably.

Some languages like Rust have so good type systems that often when a program compiles, it just works. You don't have to run the code to know that it functions if you only make a small change.

What kind of systems have you worked in? In small systems, the static analysis doesn't matter as much, but the benefits become bigger and bigger the more code there is to analyze.

Let me reverse this question and ask what is the benefit of dynamic typing? What is gained from vaguely defined objects?

The purpose of typed languages is to ensure the bare minimum when it comes to safety. That when you're accessing a field of an object that field is real, and that field is always going to be an int or a string.

Try/catch only goes so far before it becomes way more cumbersome than necessary, as is checking every field of an object.

Typescript is an example of a language that does static typing poorly, because by design it has to. It's a quick bandaid fix over an inherently awful language.

I like typescript because my API can generate types for my FE project.
So, if i change my API, i pull in fresh types and fix the errors, and i get in-ide hints for the shape of payloads, responses and events. Not everything is simple CRUD.
Also, if you pull in a library, having types is a godsend

Interesting argument. I have used both typescript and JavaScript, but I spend 99% of my time writing firmware in C, because of this I LOVE strongly typed languages, and I get kinda annoyed/paranoid when my variable COULD change type quietly so end up doing (perhaps too much) type checks etc.

I can say with surety I hate programming in both Typescript and JavaScript, but I definitely hate Typescript less because of the typing.

Having said that, I don't really like the compiled javascript that comes out of the typescript compiler, because it puts some distance between the user and the code and I am all for clarity, especially when people have to go out of their way to not run this code.