Re:Deno will stop using TypeScript
by hnarn on Sunday June 21, 2020 @12:43PM
(#23593125)
> With JS, I almost never want to verify only that a value is of a specific type; I want to look at its contents
We're pretty deep down in abstract discussions here and I have no idea what your code looks like or what it does, but I think it's helpful to point out that knowing the type means you already know the contents to some extent.
The way I see it, checking if a value is what you expect is always good, but if you additionally get an error automatically because your number is now suddenly an e-mail address, or the function you wrote that expects phone numbers suddenly gets a name instead, in my mind that's "built in testing". It doesn't make other testing unnecessary but it sure raises the bar for cleanliness -- which is especially useful when you're working with other components that aren't JS where types do really matter (like databases, for example).
We're pretty deep down in abstract discussions here and I have no idea what your code looks like or what it does, but I think it's helpful to point out that knowing the type means you already know the contents to some extent.
The way I see it, checking if a value is what you expect is always good, but if you additionally get an error automatically because your number is now suddenly an e-mail address, or the function you wrote that expects phone numbers suddenly gets a name instead, in my mind that's "built in testing". It doesn't make other testing unnecessary but it sure raises the bar for cleanliness -- which is especially useful when you're working with other components that aren't JS where types do really matter (like databases, for example).