validation

export class AppError extends Error {
  public readonly statusCode: number;
  public readonly code: string;
  public readonly isOperational: boolean;

  constructor(message: string, statusCode = 500, code = 'INTERNAL_ERROR', isOperational = true) {

const { z } = require('zod');

const envSchema = z
  .object({
    NODE_ENV: z
      .enum(['development', 'test', 'production'])

<?php

namespace App\ValueObjects;

final readonly class NotificationSettings
{

export type Validator = (value: string) => string | null;

export const required = (message = 'This field is required'): Validator => {
  return (value) => (value.trim().length === 0 ? message : null);
};

package com.example.demo.dto;

import com.example.demo.validation.UniqueEmail;
import jakarta.validation.constraints.*;
import lombok.Data;

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

from typing import Literal, Tuple, Type

from pydantic import BaseModel, PostgresDsn, RedisDsn
from pydantic_settings import (
    BaseSettings,
    PydanticBaseSettingsSource,

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Model;

from django.db import models
from django.core.exceptions import ValidationError
from django.utils import timezone


class Event(models.Model):

<?php

namespace App\Domain;

use InvalidArgumentException;

from marshmallow import (
    Schema, fields, validates, validates_schema,
    ValidationError, RAISE,
)
from marshmallow.validate import Length, Email, Equal

class OnboardingForm
  include ActiveModel::Model
  include ActiveModel::Attributes

  STEPS = %i[account profile preferences].freeze