Custom Validation Integration

Prism doesn't define its own validation DSL, custom validation is ordinary Zod or ordinary React Hook Form, both fully available through the adapters described in React Hook Form Adapter and Zod Adapter.

Cross-field validation with .refine()Copy Anchor Link

const schema = z
  .object({
    password: z.string().min(8),
    confirmPassword: z.string(),
  })
  .refine((data) => data.password === data.confirmPassword, {
    message: 'Passwords must match',
    path: ['confirmPassword'],
  });

path determines which field's field.error the message surfaces through.

Multiple independent checks with .superRefine()Copy Anchor Link

const schema = z.object({ age: z.number() }).superRefine((data, ctx) => {
  if (data.age < 18) {
    ctx.addIssue({ code: 'custom', message: 'Must be at least 18', path: ['age'] });
  }
  if (data.age > 120) {
    ctx.addIssue({ code: 'custom', message: 'Enter a realistic age', path: ['age'] });
  }
});

Async validationCopy Anchor Link

A Zod schema can validate asynchronously (.refine(async (value) => ..., message)), and createZodResolver adapts it the same way as a synchronous schema, @hookform/resolvers/zod handles both. Submission waits for the resolver to resolve before handleSubmit's success or failure callback runs, exactly as it would with plain React Hook Form and @hookform/resolvers/zod.

Conditional validation (native RHF)Copy Anchor Link

For validation that depends on something outside the Zod schema's own shape, for example a feature flag or a value from form.watch(), use RHF's native per-field rules through PrismField:

<PrismField
  form={form}
  name="promoCode"
  rules={{
    validate: (value) => (requiresPromoCode ? Boolean(value) || 'Promo code required' : true),
  }}
/>

See Combining RHF and Zod for how this interacts with a whole-form resolver on the same form.