zod-class

This is a small utility library to accompany Zod to enable for Types and Schemas to be defined in one line by creating a Class.

Installation

npm install zod-class

Usage

import z from "zod";
import { ZodClass } from "zod-class";

// define a class using a zod schema
export class Hello extends ZodClass({
  hello: z.string(),
}) {}

const hello = new Hello({
  hello: "sam",
});

// extend a class
export class World extends Hello.extend({
  world: z.string()
}) {}

const world = new World({
  hello: "world",
  world: "hello"
});

Why?

It can be annoying to always have redundant declarations for types and schemas:

the z.object declaration
the derived type using z.infer

interface HelloSchema extends z.infer<typeof HelloSchema> {}
const HelloSchema = z.object({
  key: z.string(),
});

zod-class enables this to be achieved in a single line.

It also provides a class that can be instantiated and methods added to.

export class Person extends ZodClass({
  firstName: z.string(),
  lastName: z.string(),
}) {
  get fullName() {
    return `${this.firstName} ${this.lastName}`;
  }
}

Caveats

Caveat: the static HelloSchema.parse's return type does not accurately reflect that it returns an instance of the created class,

const unknownValue: unknown;

// we wish it was `HelloSchema`, not `{ key: string }`.
const hello2: {
  key: string;
} = HelloSchema.parse(unknownValue);

Workaround: just cast it

// option 1
const hello: HelloSchema = HelloSchema.parse(unknownValue);

// option 2
const hello = HelloSchema.parse<HelloSchema>(unknownValue);