A new version of TS-Pattern is out 🚨

You can now customize the fallback behavior of `.exhaustive()` if the runtime value you get is unexpected.

upgrade 👉 npm i ts-pattern@5.7.0

Here is another reason I like Type Catalogs.

They can easily be transformed with Mapped Types!

Full code snippet in thread 🧵👇

You need to understand how unions distribute over conditional types to fully get why `Extract` works. Its definition can be somewhat cryptic:

yea ultimately unions and catalogs encode the same information so either option works!

To extract a member of a discriminated union, I find that using the builtin Extract utility is the simplest, but I've noticed that the way Extract works isn't immediately intuitive to most people

And lastly, it makes writing generic function types so much easier!

No need for pesky `Extract`s or `Exclude`s 🔥

Secondly, you can generate sub-unions super easily:

Firstly, having a catalog greatly decreases the number of type imports you need to make:

Pro tip: Don't write your #TypeScript union types by hand, use a Type Catalog instead!

Why are Type Catalogs better?

Find out in the thread 🧵 👇

A new TS-Pattern release is out!

👉 Prevent passing impossible patterns to `isMatching` when used with 2 parameters.
👉 `P.infer` behaves better when used in an argument position.

just run `npm i ts-pattern@v5.6.0` in your project 😊

Release note: github.com/gvergnaud/ts...

Type-Level TypeScript is on sale for Black Friday! 🚨

You can get it for 25% off! It's only 74$ to get lifetime access to all course materials.

👉 type-level-typescript.com

Enroll to learn how to craft and transform #TypeScript *types* with the same ease you handle JavaScript values every day!

Template Literal Types are awesome.

If you concat `number` and a union of time units, you have a human readable AND type-safe way to provide time values! 👇