Getting Started

Minimal Setup

Installation:

composer require digitalrevolution/utils

Add the namespace to your composer.json autoload or use it directly via use statements:

use DigitalRevolution\Utils\Arrays;
use DigitalRevolution\Utils\Assert;
use DigitalRevolution\Utils\Stringify;
use DigitalRevolution\Utils\Closures;

First Use Case: Replace native array operations with safer, more expressive methods. For example, replace reset($array) with:
```
$firstItem = Arrays::first($array); // Throws exception if empty
$firstItemOrNull = Arrays::firstOrNull($array); // Returns null if empty
```
Need to normalize a list of IDs coming from a request or query string? Use the new toIntList:
```
$ids = Arrays::toIntList($request->input('ids', [])); // [1, 2, 3]
```
Where to Look First:
- Arrays: For collection manipulation (e.g., flatten, groupBy, fetchByPath, toIntList).
- Assert: For fluent validation (e.g., Assert::notNull($value)->isInstanceOf(MyClass::class)).
- Stringify: For debugging or logging (e.g., Stringify::value($complexObject)).
- Closures: For lazy initialization (e.g., Closures::unfold($closure)).

Implementation Patterns

1. Array Manipulation Workflows

Flattening Nested Arrays:
```
$flatArray = Arrays::flatten($nestedArray);
```
Useful for API responses or nested configurations.

Path-Based Access:

$value = Arrays::fetchByPath($array, ['user', 'profile', 'name']);
Arrays::assignByPath($array, ['user', 'profile', 'age'], 30);

Ideal for deeply nested Laravel config or request data.

Grouping and Mapping:

$grouped = Arrays::groupBy($users, fn($user) => $user['department']);
$mapped = Arrays::map($users, fn($user, $key) => strtoupper($user['name']));

Replace collect()->groupBy() or array_map() for type safety.

Casting to an Integer List (v1.34.0+):
```
$ids = Arrays::toIntList($request->input('ids', []));
$ids = Arrays::toIntList(explode(',', $request->query('ids', '')));
```
Ideal for normalizing query-string values, CSV imports, or form multi-selects into a consistent list<int> before passing them into whereIn(), repositories, or DTOs. Replaces array_map('intval', $values) boilerplate with a typed, single-purpose helper.

Safe Removal:

$filtered = Arrays::remove($items, fn($item) => $item->isArchived());
$filtered = Arrays::removeTypes($items, [null, 'string']);

Cleaner than manual array_filter with custom logic.

2. Assertion-Driven Validation

Fluent Chaining:
```
Assert::notNull($user)->isInstanceOf(User::class)->notFalse();
```
Replace if (!$user) throw new \RuntimeException(...) with self-documenting code.
Custom Error Messages:
```
Assert::greaterThan($age, 18, 'User must be at least 18 years old');
```
Useful in Laravel form requests or API validation.
Type-Specific Assertions:
```
Assert::isArray($config)->nonEmptyArray();
Assert::fileExists($path)->readable();
```
Validate Laravel config, file uploads, or environment variables.

3. Stringify for Debugging

Logging Complex Data:
```
\Log::debug('User data:', ['data' => Stringify::value($user)]);
```
Replace var_export or json_encode for human-readable output.

Template Rendering:

$template = "User: {user}, Status: {status}";
$rendered = str_replace(
    ['{user}', '{status}'],
    [Stringify::value($user), Stringify::value($user->status)]
);

4. Closures for Lazy Loading

Service Initialization:

$service = fn() => new ExpensiveService();
$instance = Closures::unfold($service); // Executes once

Useful for Laravel service providers or dependency injection.

Memoization:

$cache = [];
$getCached = fn($key) => $cache[$key] ?? ($cache[$key] = fetchExpensiveData($key));
$value = Closures::unfold($getCached('key'));

5. Integration with Laravel

Form Request Validation:

public function rules(): array {
    return [
        'age' => ['integer', 'min:18'],
        // Custom validation via Assert:
        'user' => ['required', 'array', 'min:1'],
    ];
}

public function withValidator($validator) {
    $validator->after(function ($validator) {
        Assert::notNull($this->user['id']);
        Assert::greaterThan($this->user['age'], 0);
    });
}

Service Providers:

public function register() {
    $this->app->singleton(ExpensiveService::class, function () {
        return Closures::unfold(fn() => new ExpensiveService());
    });
}

Normalizing Request Input for Queries:

$ids = Arrays::toIntList($request->input('ids', []));
$users = User::whereIn('id', $ids)->get();

API Responses:

return response()->json([
    'data' => Arrays::map($users, fn($user) => [
        'id' => $user['id'],
        'name' => Stringify::value($user['name']),
    ]),
]);

Gotchas and Tips

Arrays

first/last vs firstOrNull/lastOrNull: Always prefer *OrNull in Laravel controllers to avoid UndefinedArrayKeyException in views/blades.
```
$firstItem = Arrays::firstOrNull($array); // Safe for Blade
```
fetchByPath and assignByPath:
- Throws \InvalidArgumentException if path is invalid.
- Use Arrays::wrap($path) if path might be a scalar:
```
Arrays::fetchByPath($array, Arrays::wrap('user.profile'));
```
toIntList (new in v1.34.0):
- Expects an array of scalar values (strings, numerics) — pass explode(',', ...) or $request->input(...) directly.
- Be aware of the usual PHP integer-casting edge cases for non-numeric strings; validate upstream with Assert or a Form Request rule if input is untrusted (e.g. ['integer'] on ids.*).
- The result is a list (sequential integer keys). Wrap your source with array_values() if you need to be certain, though the helper is intended to normalize this for you.
- Great paired with Assert::isList(...) for asserting the shape you feed into whereIn() or repository methods.
remove Performance:
- For large arrays, Arrays::removeNull() is optimized (uses array_filter internally).
- For custom callbacks, consider array_filter + array_values if order matters.
equals vs ==:
- Arrays::equals($a, $b) ignores order and supports ComparableInterface.
- Useful for testing or comparing Laravel config arrays.

Assert

Exception Messages:
- Custom messages override default ones:
```
Assert::notNull($value, 'Custom error message');
```
- Use regex in messages for multi-part assertions (e.g., Assert::greaterThan($age, 18, 'Age must be > {0}')).
isList vs isArray:
- isList checks for sequential arrays (no gaps in keys).
- Useful for Laravel collections or API payloads:
```
Assert::isList($response['data']);
```
File Assertions:
- fileExists and readable/writable are Laravel-friendly for storage paths:
```
Assert::fileExists(storage_path('app/logs/error.log'))->readable();
```
Nested Assertions:
- Messages for nested assertions (e.g., Assert::notNull($user)->isInstanceOf(User::class)) require explicit message passing:
```
Assert::notNull($user, 'User not found')->isInstanceOf(User::class, 'Invalid user type');
```

Stringify

Edge Cases:
- Stringify::value(null) returns 'null'.
- Stringify::value([]) returns 'empty-array'.
- Stringify::value(new DateTime()) returns '2023-10-01T00:00:00+00:00'.
- For JsonSerializable, uses json_encode($value, JSON_THROW_ON_ERROR).
Debugging:
- Use in Laravel app/Exceptions/Handler.php for exception debugging:
```
report(new \RuntimeException(Stringify::value($context)));
```

Closures

unfold Behavior:

Executes the closure only once, even if called multiple times.

Useful for Laravel service containers or singleton services:

$service = fn() => new DatabaseConnection();
$connection = Closures::unfold($service); // Executes once

Gotcha: Reassigning the closure variable resets the unfolded value:

$service = fn() => new Service();
$instance1 = Closures::unfold($service); // Executes
$service = fn() => new AnotherService(); // Resets!
$instance2 = Closures::unfold($service); // Executes again

General Tips

PHPStan/Laravel IDE Helper:
- The package includes PHPStan extensions for Assert methods. Enable them in phpstan.neon by including the package's extension:
```
includes:
  - vendor/digitalrevolution/utils/phpstan-extension.neon
```
Dev tooling only changes: v1.34.0 bumps phpmd/phpmd to v3. This is a dev dependency used by the package itself for its own code quality checks. It has no runtime impact on your application and requires no action on your side.
Upgrading: v1.34.0 is additive — no breaking changes. A composer update digitalrevolution/utils is enough; you can start using Arrays::toIntList immediately.

Utils Laravel Package