TypeScript-wiki VS zod

What's prompted me to look at this is my tRPC+Zod editor experience at work has become unusable. 2-3 seconds to just get autocompletion options on a tRPC path, and then another 2-3 for the next path, repeat. When investigated using TypeScript's tracing tools the data entirely points back to my team's Zod DTOs. What I learned is that Zod's performance is okay at the start, but when you start using methods like .extend/.pick/.omit (and so on) the performance regresses in the order of a magnitude. Rather than making this into a "Zod considered bad" post, I wanted to investigate how the alternatives which can be integrated with tRPC fare, and see whether I can do better.

When you can write a busy beaver machine in the type system, LOC ceases to be a good indicator or how long something should take to typecheck, imo. If you're frustrated with your build, you should use the trace tools on the TS wiki[1] to track down what types are slow to check, so you can attribute the slowness to the appropriate library authors/yourself and decide for yourself if the speed/correctness tradeoff they've made is right for you.

[1]https://github.com/microsoft/TypeScript-wiki/blob/main/Perfo...

Good spot to start: https://github.com/microsoft/TypeScript-wiki/blob/main/Performance-Tracing.md

So I want to update my (very large*) project from TypeScript 2.3.3 to the latest version, and I know that a breaking changes doc exists.

[Zod Documentation](https://zod.dev/) [Zod Error Handling](https://zod.dev/ERROR_HANDLING?id=error-handling-in-zod) [React-Hook-Form Documentation](https://react-hook-form.com/get-started) [Hookform Resolvers](https://www.npmjs.com/package/@hookform/resolvers)

This is a very fair comment, and you seem open to understanding why types are useful.

"problems that are due to typing" is a very difficult thing to unpack because types can mean _so_ many things.

Static types are absolutely useless (and, really, a net negative) if you're not using them well.

Types don't help if you don't spend the time modeling with the type system. You can use the type system to your advantage to prevent invalid states from being represented _at all_.

As an example, consider a music player that keeps track of the current song and the current position in the song.

If you model this naively you might do something like: https://gist.github.com/shepherdjerred/d0f57c99bfd69cf9eada4...

In the example above you _are_ using types. It might not be obvious that some of these issues can be solved with stronger types, that is, you might say that "You rarely see problems that are due to typing".

Here's an example where the type system can give you a lot more safety: https://gist.github.com/shepherdjerred/0976bc9d86f0a19a75757...

You'll notice that this kind of safety is pretty limited. If you're going to write a music app, you'll probably need API calls, local storage, URL routes, etc.

TypeScript's typechecking ends at the "boundaries" of the type system, e.g. it cannot automatically typecheck your fetch or localStorage calls return the correct types. If you're casting, you're bypassing the type systems and making it worthless. Runtime type checking libraries like Zod [0] can take care of this for you and are able to typecheck at the boundaries of your app so that the type system can work _extremely_ well.

[0]: https://zod.dev/ note: I mentioned Zod because I like it. There are _many_ similar libraries.

Zod is an open-source schema declaration and validation library that emphasizes TypeScript. It can refer to any data type, from simple to complex. Zod eliminates duplicative type declarations by inferring static TypeScript types and allows easy composition of complex data structures from simpler ones. It has no dependencies, is compatible with Node.js and modern browsers, and has a concise, chainable interface. Zod is lightweight (8kb when zipped), immutable, with methods returning new instances. It encourages parsing over validation and is not limited to TypeScript but works well with JavaScript as well.

Zod is a TypeScript-first schema declaration and validation library. It helps create schemas for any data type and is very developer-friendly. Zod has the functional approach of "parse, don't validate." It supports coercion in all primitive types.

Link: https://zod.dev/

You can check out their documentation here.

You can learn more about Zod on their website here.

In JS, it's a good idea anyway to use some JSON parsing library instead of JSON.parse.

With Zod, you can use z.bigint() parser. If you take the "parse any JSON" snippet https://zod.dev/?id=json-type and change z.number() to z.bigint(), it should do what you are looking for.

We will validate our input using client-side zod. Zod handles TypeScript-first schema validation with static type inference. This means that it will not only validate your fields, it will also set types on validated fields.