true-myth VS zod

TS doesn't do anything at runtime no, but there are some type checking libraries that could help you. I don't know what packages you're talking about in particular, but if they are IO related you can try io-ts. More generally you could also look into true-myth for Maybe types and wrap any values that come out of your packages before allowing them to be passed into your code.

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.

A word of warning: while discriminated unions are very powerful, there's an ongoing discussion on whether discriminated unions should be deprecated and replaced with a different API.

I was first introduced to Zod by Adam Bobrow - a colleague of mine and a dear friend. Adam was sick and tired from JavaScript's brittleness, and about two years ago he started migrating our code base to TypeScript. But that wasn't enough for him. He kept complaining: "What good are my types, if some other service decides to send me bad data and breaks my code?". That's when he discovered Zod.