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YPChen

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Using Valibot for Recursive Schema Validation

#typescript #demo #valibot

Valibot's playground for the code demo

Recursive Type in TypeScript

TypeScript allows defining recursive types. For example, consider the following User interface:

interface User { children?: User; email: `${string}@${string}`; password: string; }
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Using Valibot for Schema Validation

What if you use a schema library, like Zod or Valibot? The schema has been built on value-level, and you cannot assign the variant to its property inside the declaration.

import * as v from 'valibot'; const EmailSchema = v.string([v.minLength(1), v.email()]); const PasswordSchema = v.string([v.minLength(1), v.minLength(8)]); // const UserSchema?
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Recursive Schema

Base on the Author's reply in this issue, you can use v.lazy(() => UserSchema) and to create a type of the UserSchema as a type param to the v.BaseSchema genre as a type inference of the UserSchema:

type UserSchemaType = { children?: UserSchemaType; email: v.Input<typeof EmailSchema>; password: v.Input<typeof PasswordSchema>; } const UserSchema: v.BaseSchema<UserSchemaType> = v.object({ children: v.optional(v.lazy(() => UserSchema)), email: EmailSchema, password: PasswordSchema, });
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Top comments (1)

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lashawty profile image
Sean •

nice