JSDoc VS zod

You may like JSDoc[1] if you just want some type-safety from the IDE without the compilation overhead.

It’s done wonders when I’ve had to wrangle poorly commented legacy JavaScript codebases where most of the overhead is tracing what type the input parameters are.

Personally, I’m impartial to TypeScript or JSDoc at this point. But I’d rather have either over plain JavaScript.

[1] https://jsdoc.app/

I wholeheartedly agree. At most, I introduce JSDoc[1] to newer developers as standardising how parameters and whatnot are commented at least gets you better documentation and _some_ safety without adding any TS knowledge overhead.

[1] https://jsdoc.app/

This is where JSDoc comes to save the day.

The best way to do this, of course, is with JSDoc. But something I always found awkward about jsdoc is defining the object types in the same file. So, after a lot of reading, I found a way to combine JSDoc with declaration type files from Typescript. Let me give you an example:

There is a lot of specific symbols presented on the JSDOC specification that can be found here: https://jsdoc.app

JSDoc is a specification for the comment format in JavaScript. This specification allows developers to describe the structure of their code, data types, function parameters, and much more using special comments. These comments can then be transformed into documentation using appropriate tools.

Working with new features, frameworks, and tools, the experience of reading documentation is a critical part of it. I have been lucky to work with projects that feature really easy to read documentation such as USWDS and Bun, but I've also had the misfortune to work with pretty terrible documentation like JSDoc. The JSDoc documentation lacks a search field which makes searching for specific items an ordeal and also does not cover many hidden use cases. It provides less than the bare minimum for what it needs to do - a lot of the time I am forced to rely on external user documentation elsewhere to use JSDoc effectively. That was why I was drawn to the search field in particular in Docusaurus.

The Svelte team followed suit but motivated by the maintainer's developer experience as they migrated the project away from TypeScript in favor of plain JSDoc comments for type annotations instead.

Even more relevant, tools like Javadoc, JSDoc, Doxygen, etc. read comments in a specific format to generate documentation. These comments do not affect readability. On the contrary, Javadocs are great for explaining how to use these entities. Combined with tools like my dear Doctest, we even get guarantees of accuracy and correctness!

Document types with JSDoc annotations

[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.