Custom Validators

Introduction

Automatically created Zod types for primitive fields may not always meet all your requirements. For example, for a field with the Attr attribute, a schema of type z.unknown() is created by default. This limits the possibilities for validating structures.

Additionally, there might be cases where you need to ensure that a string is longer than a certain number of characters, or a number is less than a specific maximum value.

For these situations, you can assign your own Zod schemas to any of the fields. This can be done in two ways, which will be discussed below.

Important

The schema you define does not supplement but replaces the automatically generated one. Keep this in mind when writing types.

Definition Through Static Property

For both JavaScript and TypeScript, you can define your own schemas for fields using a static property of your model's class, similar to how the entity property is defined:

import { z } from 'zod'

export class User extends Model {
  public static entity = 'user'
  
  public static $zodSchemas = {
    age: z.number().gt(18)
  }
  
  @NumberField(0)
  public age: number
}

As a result, the age property will be validated using the schema you defined, while other fields will continue to work as before. The basic validation for Num will not work.

Definition Through Decorators

The same can be achieved using the ZodFieldType decorator:

import { z } from 'zod'
import { ZodFieldType } from '@rattus-orm/plugin-zod-validate'

export class User extends Model {
  public static entity = 'user'

  @ZodFieldType(z.number().gt(18))
  @NumberField(0)
  public age: number
}