laravel-value-objects skill

---
name: laravel-value-objects
description: Immutable value objects for domain values. Use when working with domain values, immutable objects, or when user mentions value objects, immutable values, domain values, money objects, coordinate objects.
---

# Laravel Value Objects

Value objects are **simple, immutable objects** representing domain concepts.

**Related guides:**
- [DTOs](../laravel-dtos/SKILL.md) - DTOs are for data transfer, value objects for domain concepts

## When to Use

**Use value objects when:**
- Complex domain value with behavior
- Immutability required
- Rich validation logic
- Need equality comparison
- Encapsulating domain rules

**Use DTOs when:**
- Transferring data between layers
- No domain behavior needed
- See [DTOs](../laravel-dtos/SKILL.md)

## Simple Value Object

```php
<?php

declare(strict_types=1);

namespace App\Values;

use App\Enums\ProcessResult as ProcessResultEnum;

class ProcessResult
{
    public function __construct(
        public readonly ProcessResultEnum $result,
        public readonly ?string $message = null,
    ) {}

    public static function success(?string $message = null): self
    {
        return new self(ProcessResultEnum::Success, $message);
    }

    public static function skip(?string $message = null): self
    {
        return new self(ProcessResultEnum::Skip, $message);
    }

    public static function fail(?string $message = null): self
    {
        return new self(ProcessResultEnum::Fail, $message);
    }

    public function isSuccess(): bool
    {
        return $this->result === ProcessResultEnum::Success;
    }

    public function isFail(): bool
    {
        return $this->result === ProcessResultEnum::Fail;
    }
}
```

## Money Value Object

**[View full implementation →](references/Money.php)**

## Usage Examples

### ProcessResult

```php
// In actions
return ProcessResult::success('Order processed successfully');
return ProcessResult::skip('Order already processed');
return ProcessResult::fail('Payment declined');

// Checking results
if ($result->isSuccess()) {
    // Handle success
}

if ($result->isFail()) {
    // Handle failure
}
```

### Money

```php
// Creating money values
$price = Money::fromDollars(29.99);
$tax = Money::fromDollars(2.40);
$shipping = Money::fromCents(500);  // $5.00

// Operations
$subtotal = $price->add($tax);
$total = $subtotal->add($shipping);

// Multiplication
$bulkPrice = $price->multiply(10);

// Display
echo $total->formatted();  // "37.39"

// Comparison
if ($total->equals($expectedTotal)) {
    // Amounts match
}
```

## Key Patterns

### 1. Immutability

Use `readonly` properties:

```php
public readonly int $amount;
public readonly string $currency;
```

### 2. Static Factory Methods

Named constructors for common scenarios:

```php
public static function fromDollars(float $dollars): self
public static function success(?string $message = null): self
```

### 3. Private Constructor

Force use of factory methods:

```php
private function __construct(/* ... */) {}
```

### 4. Domain Logic

Encapsulate domain rules:

```php
public function add(Money $other): self
{
    $this->assertSameCurrency($other);
    return new self($this->amount + $other->amount, $this->currency);
}
```

### 5. Return New Instances

Operations return new instances (immutability):

```php
public function add(Money $other): self
{
    return new self($this->amount + $other->amount, $this->currency);
}
```

## Directory Structure

```
app/Values/
├── Money.php
├── ProcessResult.php
├── Coordinate.php
└── EmailAddress.php
```

## Summary

**Value objects:**
- Are immutable (use `readonly`)
- Have static factory methods
- Encapsulate domain logic
- Return new instances from operations
- Validate in constructor

**Use for domain concepts with behavior, not simple data transfer.**