How to validate Zod Object depending on value of parent object

Question

I have a zod schema like this:

export const memberSchema = z
  .object({
    name: z.string().min(3),
    lastname: z.string().min(3),
    nationality: zCountries,
    birthdate: z.date(),
    email: z.string().email(),
    tutor: z
      .object({
        name: z.string(),
        lastname: z.string(),
        documentType: zDocumentationType,
        documentValue: z.string(),
        email: z.string().email(),
        phone: z.string().regex(/^\d{9}$/)
      })
  }).refine((data) => .....)

Is it possible to validate tutor object is required only if birthdate is under 18 ? Because if member is +18 this fields are not needed.

I know how to validate a field depending of another one in refine function, but I don't know how to validate and entire object...

EXAMPLE:

• { birthdate: '20/02/2015'} -> ALL Fields in tutor has to be filled and passing zod tutor object validation
• {birthdate: '09/05/1988' } -> Tutor object is undefined and returns true.

Answer 1

After many tries I got what I want with z.union between object and undefined and super refine.

Here is my code. Hope it helps someone in future.

export const memberSchema = z
  .object({
    name: z.string().min(3),
    lastname: z.string().min(3),
    nationality: zCountries,
    birthdate: z.date(),
    email: z.string().email(),
    tutor: z.union([
      z.object({
        name: zTutorString,
        lastname: zTutorString,
        document: zTutorString,
        email: zTutorString.email(),
        phone: zTutorString.regex(/^\d{9}$/)
      }),
      z.undefined()
    ])
  })
  .superRefine((data, ctx) => {
    const validation =
      data.birthdate.getFullYear() + 18 < new Date().getFullYear() ||
      (data.birthdate.getFullYear() + 18 > new Date().getFullYear() && data.tutor !== undefined)
    if (!validation) {
      tutorFields.forEach((field) => {
        if (!data.tutor || (data.tutor && !data.tutor[field as keyof typeof data.tutor])) {
          ctx.addIssue({
            code: z.ZodIssueCode.custom,
            message: i18n.t('validation.required_tutor'),
            path: ['tutor', field]
          })
        }
      })
    }
  })