Type-checked non-empty strings

Discussion (9 Comments)Read Original on HackerNews

muglug•about 1 hour ago

Very cool that the language allows specification of a type in this way.

I added a similar type — “non-empty-string” to a typechecker for PHP, and it’s been adopted widely in the PHP ecosystem. It turns out to be pretty handy, especially when there’s a full type system to support it.

IshKebab•about 1 hour ago

"Huh never heard of Bellroy... I wonder what they're using Haskell for..."

Turns out it's some kind of bags and accessories brand!

qbane•about 1 hour ago

I pondered for a while, it IS the company I used to know

ivanjermakov•about 1 hour ago

Language is not mentioned in a title, so my first thought was about TypeScript type wizardry. Turns out it's as simple as `Exclude<string, "">`.

https://www.typescriptlang.org/docs/handbook/utility-types.h...

antipurist•about 1 hour ago

It's simple, and it doesn't work as `Exclude` only applies to union types. For type `string` it just returns the same type `string`.

phpnode•25 minutes ago

yup, it's not possible to do it safely with a simple unparameterised type: https://www.typescriptlang.org/play/?#code/C4TwDgpgBAcg9gOwK...

ralferoo•about 1 hour ago

It is very much mentioned in the article title and the first sentence. It's just HN that's truncated the title.

Type-checked non-empty strings

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Discussion (9 Comments)Read Original on HackerNews