Migration

Migration guide from other validation libraries to Seal.

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From Zod

Basic Migration

// Before (Zod)
import { z } from "zod";

const userSchema = z.object({
  email: z.string().email(),
  password: z.string().min(8),
  age: z.number().min(18)
});

// After (Seal)
import { v, type Infer } from "@warlock.js/seal";

const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8),
  age: v.number().required().min(18)
});

Advanced Migration

// Before (Zod)
const userSchema = z.object({
  email: z.string().email().transform(val => val.toLowerCase().trim()),
  password: z.string().min(8).refine(val => isStrongPassword(val)),
  confirmPassword: z.string()
}).refine(data => data.password === data.confirmPassword, {
  message: "Passwords must match",
  path: ["confirmPassword"]
});

// After (Seal)
const userSchema = v.object({
  email: v.string().required().email().lowercase().trim(),
  password: v.string().required().minLength(8).strongPassword(),
  confirmPassword: v.string().required().sameAs("password")
});

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From Joi

Basic Migration

// Before (Joi)
import Joi from "joi";

const userSchema = Joi.object({
  email: Joi.string().email().required(),
  password: Joi.string().min(8).required(),
  age: Joi.number().min(18).required()
});

// After (Seal)
import { v, type Infer } from "@warlock.js/seal";

const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8),
  age: v.number().required().min(18)
});

Advanced Migration

// Before (Joi)
const userSchema = Joi.object({
  email: Joi.string().email().required().lowercase().trim(),
  password: Joi.string().min(8).required().custom((value, helpers) => {
    if (!isStrongPassword(value)) {
      return helpers.error('password.weak');
    }
    return value;
  }),
  confirmPassword: Joi.string().required().valid(Joi.ref('password'))
});

// After (Seal)
const userSchema = v.object({
  email: v.string().required().email().lowercase().trim(),
  password: v.string().required().minLength(8).strongPassword(),
  confirmPassword: v.string().required().sameAs("password")
});

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From Yup

Basic Migration

// Before (Yup)
import * as yup from "yup";

const userSchema = yup.object({
  email: yup.string().email().required(),
  password: yup.string().min(8).required(),
  age: yup.number().min(18).required()
});

// After (Seal)
import { v, type Infer } from "@warlock.js/seal";

const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8),
  age: v.number().required().min(18)
});

Advanced Migration

// Before (Yup)
const userSchema = yup.object({
  email: yup.string().email().required().lowercase().trim(),
  password: yup.string().min(8).required().test('strong', 'Password must be strong', isStrongPassword),
  confirmPassword: yup.string().required().oneOf([yup.ref('password')], 'Passwords must match')
});

// After (Seal)
const userSchema = v.object({
  email: v.string().required().email().lowercase().trim(),
  password: v.string().required().minLength(8).strongPassword(),
  confirmPassword: v.string().required().sameAs("password")
});

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From Ajv

Basic Migration

// Before (Ajv)
import Ajv from "ajv";

const userSchema = {
  type: "object",
  properties: {
    email: { type: "string", format: "email" },
    password: { type: "string", minLength: 8 },
    age: { type: "number", minimum: 18 }
  },
  required: ["email", "password", "age"],
  additionalProperties: false
};

// After (Seal)
import { v, type Infer } from "@warlock.js/seal";

const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8),
  age: v.number().required().min(18)
});

Advanced Migration

// Before (Ajv)
const userSchema = {
  type: "object",
  properties: {
    email: { type: "string", format: "email" },
    password: { type: "string", minLength: 8 },
    confirmPassword: { type: "string" }
  },
  required: ["email", "password", "confirmPassword"],
  additionalProperties: false,
  if: {
    properties: { password: { type: "string" } }
  },
  then: {
    properties: {
      confirmPassword: { const: { $data: "1/password" } }
    }
  }
};

// After (Seal)
const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8),
  confirmPassword: v.string().required().sameAs("password")
});

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From Class Validator

Basic Migration

// Before (Class Validator)
import { IsEmail, IsString, MinLength, IsNumber, Min } from "class-validator";

class User {
  @IsEmail()
  @IsString()
  email: string;

  @IsString()
  @MinLength(8)
  password: string;

  @IsNumber()
  @Min(18)
  age: number;
}

// After (Seal)
import { v, type Infer } from "@warlock.js/seal";

const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8),
  age: v.number().required().min(18)
});

Advanced Migration

// Before (Class Validator)
import { IsEmail, IsString, MinLength, Matches, ValidateIf } from "class-validator";

class User {
  @IsEmail()
  @IsString()
  email: string;

  @IsString()
  @MinLength(8)
  @Matches(/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]/, {
    message: "Password must be strong"
  })
  password: string;

  @IsString()
  @ValidateIf(o => o.password)
  @Matches('password')
  confirmPassword: string;
}

// After (Seal)
const userSchema = v.object({
  email: v.string().required().email(),
  password: v.string().required().minLength(8).strongPassword(),
  confirmPassword: v.string().required().sameAs("password")
});

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Migration Checklist

1. Install Seal

npm install @warlock.js/seal

2. Update Imports

// Before
import { z } from "zod";
import Joi from "joi";
import * as yup from "yup";

// After
import { v, type Infer } from "@warlock.js/seal";

3. Convert Schemas

// Before
const schema = z.object({
  name: z.string().min(2),
  email: z.string().email()
});

// After
const schema = v.object({
  name: v.string().required().minLength(2),
  email: v.string().required().email()
});

4. Update Type Inference

// Before
type User = z.infer<typeof userSchema>;

// After
type User = Infer<typeof userSchema>;

5. Update Validation Calls

// Before
const result = userSchema.parse(data);

// After
const result = await validate(userSchema, data);

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Common Migration Issues

1. Required Fields

// Before (Zod)
const schema = z.object({
  name: z.string(), // Optional by default
  email: z.string().email()
});

// After (Seal)
const schema = v.object({
  name: v.string().required(), // Explicitly required
  email: v.string().required().email()
});

2. Error Handling

// Before (Zod)
try {
  const result = userSchema.parse(data);
  return result;
} catch (error) {
  if (error instanceof z.ZodError) {
    return { errors: error.errors };
  }
}

// After (Seal)
const result = await validate(userSchema, data);
if (!result.isValid) {
  return { errors: result.errors };
}
return result.data;

3. Custom Validation

// Before (Zod)
const schema = z.string().refine(val => val.length > 5, {
  message: "Must be at least 6 characters"
});

// After (Seal)
const schema = v.string().refine((value, context) => {
  if (value.length < 6) {
    return "Must be at least 6 characters";
  }
  return undefined;
});

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Performance Benefits

Bundle Size Reduction

// Before (Zod)
import { z } from "zod"; // ~25KB

// After (Seal)
import { v } from "@warlock.js/seal"; // ~15KB

Validation Speed

// Before (Zod)
const result = userSchema.parse(data); // Slower

// After (Seal)
const result = await validate(userSchema, data); // Faster

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See Also

• Cookbook - Common validation patterns
• Best Practices - Validation best practices
• Comparison - Compare with other libraries