@schemashift/yup-zod

Yup ↔ Zod transformer for SchemaShift. Supports both forward (Yup → Zod) and backward (Zod → Yup) migrations.

Installation

npm install @schemashift/yup-zod

Usage

import { createYupToZodHandler, createZodToYupHandler } from '@schemashift/yup-zod';
import { TransformEngine } from '@schemashift/core';

const engine = new TransformEngine();
engine.registerHandler('yup', 'zod', createYupToZodHandler());
engine.registerHandler('zod', 'yup', createZodToYupHandler()); // Backward migration (Pro+)

Backward Migration: Zod → Yup

AST-based transformer that converts Zod schemas back to Yup equivalents:

| Zod | Yup | |-----|-----| | z.object({...}) | yup.object({...}) | | z.string() | yup.string() | | z.number() | yup.number() | | z.boolean() | yup.boolean() | | z.date() | yup.date() | | z.array(s) | yup.array().of(s) | | .optional() | .notRequired() | | .nullable() | .nullable() | | .refine(fn, msg) | .test('custom', msg, fn) | | z.enum([...]) | yup.mixed().oneOf([...]) | | z.union([...]) | yup.mixed().oneOf([...]) | | z.literal(val) | yup.mixed().oneOf([val]) | | z.record(k, v) | yup.object() (with TODO) | | z.tuple([...]) | yup.array() (with TODO) |

Tier: Pro+

Transformation Mappings

Imports

| Yup | Zod | |-----|-----| | import * as yup from 'yup' | import { z } from 'zod' | | import yup from 'yup' | import { z } from 'zod' |

Basic Types

| Yup | Zod | |-----|-----| | yup.string() | z.string() | | yup.number() | z.number() | | yup.boolean() | z.boolean() | | yup.date() | z.date() | | yup.array() | z.array() | | yup.object() | z.object() | | yup.mixed() | z.unknown() |

Required/Optional

| Yup | Zod | Notes | |-----|-----|-------| | .required() | (removed) | Zod fields are required by default | | .notRequired() | .optional() | | | .nullable() | .nullable() | | | .defined() | (removed) | Handled by Zod's type system |

String Validations

| Yup | Zod | |-----|-----| | .email() | .email() | | .url() | .url() | | .uuid() | .uuid() | | .min(n) | .min(n) | | .max(n) | .max(n) | | .length(n) | .length(n) | | .matches(regex) | .regex(regex) | | .lowercase() | .toLowerCase() | | .uppercase() | .toUpperCase() | | .trim() | .trim() |

Number Validations

| Yup | Zod | |-----|-----| | .min(n) | .min(n) | | .max(n) | .max(n) | | .positive() | .positive() | | .negative() | .negative() | | .integer() | .int() |

Array Validations

| Yup | Zod | |-----|-----| | .min(n) | .min(n) | | .max(n) | .max(n) | | .length(n) | .length(n) | | .of(schema) | z.array(schema) |

Object Methods

| Yup | Zod | |-----|-----| | .shape({...}) | z.object({...}) | | .pick([...]) | .pick({...}) | | .omit([...]) | .omit({...}) | | .partial() | .partial() | | .strict() | .strict() | | .passthrough() | .passthrough() |

Other

| Yup | Zod | |-----|-----| | .default(value) | .default(value) | | .oneOf([...]) | z.enum([...]) or z.literal().or(...) | | .test(...) | .refine(...) | | .transform(...) | .transform(...) |

Patterns Requiring Manual Review

The transformer generates actionable .superRefine() scaffolding for these patterns (not bare TODOs):

.when() Conditionals

Yup's .when() doesn't have a direct Zod equivalent. The transformer generates a .superRefine() template with the original condition context:

// Yup
const schema = yup.object({
  isBusiness: yup.boolean(),
  companyName: yup.string().when('isBusiness', {
    is: true,
    then: yup.string().required(),
  }),
});

// Generated output (with scaffolding)
/* TODO(schemashift): Convert conditional validation.
   Original: .when('isBusiness', { is: true, then: ..., otherwise: ... })
   Suggested Zod equivalent:
   .superRefine((data, ctx) => {
     if (data.isBusiness === true) {
       // Apply 'then' validation
     } else {
       // Apply 'otherwise' validation
     }
   })
*/
const schema = z.object({
  isBusiness: z.boolean(),
  companyName: z.string().optional(),
}).superRefine((data, ctx) => {
  if (data.isBusiness && !data.companyName) {
    ctx.addIssue({
      code: z.ZodIssueCode.custom,
      message: 'Company name required for business accounts',
      path: ['companyName'],
    });
  }
});

.test() Custom Validations

Complex .test() calls may need adjustment for Zod's .refine() API.

// Yup
yup.string().test('custom', 'Invalid', (value) => customValidation(value))

// Zod
z.string().refine((value) => customValidation(value), 'Invalid')

Async Validations

Yup supports async validation in .test(). Zod requires explicit async handling.

// Yup
yup.string().test('unique', 'Already exists', async (value) => {
  return await checkUnique(value);
})

// Zod
z.string().refine(async (value) => {
  return await checkUnique(value);
}, 'Already exists')
// Note: Use .parseAsync() instead of .parse()

Related Packages

• schemashift-cli — CLI tool for running migrations
• @schemashift/core — Core analysis engine
• @schemashift/zod-valibot — Chain: Yup → Zod → Valibot
• @schemashift/zod-v3-v4 — Upgrade Zod after migration

License

MIT