bignumber.js VS zod

If you use floating-points for currency (instead of whole-numbers like you probably should) libraries like bignumber.js help keep your code away from the binary floating-point pitfalls of IEEE-754 which manifests in the standard JavaScript number type:

This issue (well, another one in a widely used JS library) is what brought me to dig deeper into these "arbitrary precision" libraries and understand why this happens. I thought they were using rational numbers, but that's not the case. And this is what led me to think about how to solve this problem.

ERC20 has decimals fields and must be handled with digit awareness. I wanted to use only one library, but I used both ether.js's BigNumber and bignumber.js (for display purpose).

Most programming languages ( JavaScript, PHP, Go, Python, Java, C# ) have built-in support or 3rd-party libraries for handling this data type, even though the internal implementations can differ:

I'm working on a project where users will enter numbers like 9,999,999,999.99999 (up to 15 digits, up to 5 of them decimal) and we are having a problem with Numbers losing precision beyond certain number of digits (a typical issue for IEEE Standard 754 Floating Point Numbers, the 0.1 + 0.2 problem). I've solved this problem in a few projects before with the help of decimal.js or bignumber,js . In those cases, we kept user-input as strings and used a few custom-made numeric textbox widgets to accommodate this. Unfortunately, those widgets were proprietary... Now I need one again, but can't find anything. Do they exist?

Either avoid floating-point, perhaps using BigInt, or use a library like BigNumber.js. (Incidentally, I wrote an eslint plugin to enforce its use.)

To solve the problem while JavaScript waits on its own BigDecimal API, you can use something like bignumber.js to perform your calculations.

You need to use something like BigNumber.js

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.