Pest 4

Overview Livewire 4 represents a massive leap forward for the Laravel ecosystem, focusing on developer experience and performance without the pain of a total rewrite. This update addresses the fragmentation within the community by unifying component styles—combining the best of Volt and traditional class-based components. By introducing the **Blaze compiler** and **Islands architecture**, the framework tackles the "Livewire is slow" myth head-on, offering tools that can speed up page rendering by up to 10x while maintaining the reactive, "no-JavaScript-required" workflow that developers love. Prerequisites To follow along with these techniques, you should have a solid grasp of: * **PHP & Laravel basics**: Understanding of routing, Blade templates, and class structures. * **Livewire 3**: Familiarity with how state and actions work in the current version. * **Alpine.js**: Basic knowledge of client-side reactivity. * **Tailwind CSS**: Useful for implementing the new loading indicator patterns. Key Libraries & Tools * **Livewire 4**: The core full-stack framework for Laravel. * **Blaze**: A new optimization layer that "code-folds" Blade components to remove runtime overhead. * **Pest 4**: A testing framework used for high-level browser testing within components. * **Flux UI**: A high-quality component kit that benefits from these performance upgrades. * **Sushi**: An array-to-Eloquent driver mentioned as a community favorite. Code Walkthrough: The Unified Component Model In Livewire 4, the goal is to stop the confusion between functional, class-based, and Volt styles. The new default is a single-file, class-based structure located in `resources/views/components` alongside your standard Blade components. Single-File Components Creating a counter now looks like this: ```php <?php use function Livewire\{state, rules}; new class extends Livewire\Component { public $count = 0; public function increment() { $this->count++; } }; ?> <div> <button wire:click="increment">+</button> <span>{{ $count }}</span> </div> <script> this.watch('count', (value) => { console.log('Count changed to: ' + value); }); </script> ``` In this example, the logic, view, and script live together. Notice the `<script>` tag at the bottom—it no longer requires `@script` directives. The `this` keyword in JavaScript replaces the older `$wire` syntax, offering a more native feel. These scripts are served as **ES6 modules**, meaning they are cached by the browser and can use native imports. Multi-File Conversion If a component grows too large, you can automatically convert it to a **Multi-File Component (MFC)** using the CLI. This moves the logic into a dedicated directory with separate `.php`, `.blade.php`, and `.js` files, maintaining Caleb Porzio's "Single Responsibility Principle" by keeping related files collocated in one folder. Syntax Notes: PHP 8.4 Property Hooks Livewire 4 leans heavily into PHP 8.4 features to simplify state management. The most impactful change is the use of **Property Hooks**, which replace many old `updating` and `updated` lifecycle methods. Validation with Setters You can now intercept property updates directly at the language level: ```php public int $count = 0 { set => max(0, $value); } ``` Memoization with Getters Instead of creating custom computed property methods, use native getters. These are excellent for deriving state for your views: ```php public int $multiple { get => $this->count * 5; } ``` You can even use asymmetric visibility (`public get, protected set`) to make a property readable by the view but immutable from the client, effectively replacing the `@locked` attribute. The Blaze Compiler: Vaporizing Runtime Overhead One of the most impressive technical feats in version 4 is **Blaze**. Caleb Porzio identified that the primary bottleneck in large Blade views isn't PHP itself, but the overhead of resolving and merging attributes for thousands of components. Blaze uses a technique called **code folding**. It parses your Blade templates and identifies static parts—like Tailwind CSS classes or HTML structures that never change—and renders them at compile time. This turns a complex component tree back into raw, concatenated PHP strings. In benchmarks, this reduced a page with 29,000 view instances from 1.6 seconds down to just 131 milliseconds. Best of all, it works for standard Blade components, not just Livewire ones. Practical Examples: Islands and Infinite Scroll **Islands architecture** allows you to isolate expensive parts of a page so they don't block the rest of the UI. This is a game-changer for dashboards with slow database queries. Implementing an Island Wrap a slow section in the `@island` directive: ```blade @island('revenue-chart', lazy: true) <div class="chart"> {{ $this->expensiveRevenueQuery() }} </div> @placeholder <x-skeleton-loader /> @endisland ``` By setting `lazy: true`, the main page loads instantly. Livewire then makes a separate, isolated request for the island. Actions taken within the island only rerender the island itself. Infinite Pagination Islands also unlock high-performance pagination. By changing the render mode to `append`, you can create an infinite scroll effect with minimal code: ```blade @island('reports', mode: 'append') @foreach($reports as $report) <div>{{ $report->title }}</div> @endforeach @endisland <button wire:intersect="$paginator->nextPage()" wire:island="reports"> Loading more... </button> ``` The `wire:intersect` directive triggers the next page when the button enters the viewport, and because the island is in `append` mode, it only fetches and patches the new results into the DOM. Tips & Gotchas * **Priority Polling**: In Livewire 4, human-initiated actions (like clicks) now automatically cancel background polling requests. This prevents the UI from feeling "locked" when background updates are happening. * **Data Loading Attributes**: Any element triggering a request now receives a `data-loading` attribute. Use Tailwind CSS modifiers like `data-loading:opacity-50` to handle loading states without writing complex `wire:loading` logic. * **Ref Management**: Use `wire:ref="myModal"` to target specific components for events. This solves the issue of global event listeners accidentally closing every modal on the page when only one was intended. * **PHP 8.4 Requirement**: To use the advanced property hooks, you must ensure your server is running PHP 8.4. While Livewire 4 aims for "mostly no breaking changes," these specific syntax upgrades require modern PHP.