asset-manifest.json

{
  "app.css": "/css/app.1886ffa0.chunk.css",
  "app.js": "/js/app.274af2d6.chunk.js",
  "app.js.map": "/js/app.274af2d6.chunk.js.map",
  "runtime-app.js": "/js/runtime-app.3e6cdd74.js",
  "runtime-app.js.map": "/js/runtime-app.3e6cdd74.js.map",
  "css/app.1886ffa0.chunk.css.map": "/css/app.1886ffa0.chunk.css.map",
  "precache-manifest.af9e5948aed3b3d8242fe41cdde87545.js": "/precache-manifest.af9e5948aed3b3d8242fe41cdde87545.js",
  "service-worker.js": "/service-worker.js"
}

ReactBladeDirective.php

<?php
namespace React;
class ReactBladeDirective {
    /**
     * Manifest file to read
     */
    protected $manifest_files = '';
    /**
     * CRA generated assets
     */
    protected $assets = [];
    protected $css_regex = '/css/';
    protected $js_regex = '/js/';
    protected $exclude = '/(map|html|service-worker)/';
    public function __construct() {
        $this->public_path = public_path('asset-manifest.json');
        $this->manifest_file = file_get_contents($this->public_path);
        $this->assets_array = json_decode($this->manifest_file, true);
        $this->assets = collect($this->assets_array)->reject(function ($key, $value) {
            return preg_match($this->exclude, $key);
        });
    }
    public function css($only) {
        $css = $this->assets->reject((function($key, $value) {
            return preg_match($this->js_regex, $key);
        }))->map(function ($url) {
            return '<link rel="stylesheet" type="text/css" href="' . $url . '" />';
        })->toArray();
        return implode(' ', $css);
    }
    public function js($only) {
        $js = $this->assets->reject((function($key, $value) {
            return preg_match($this->css_regex, $value);
        }))->map(function ($url) {
            return '<script src="' . $url . '"></script>';
        })->reverse()->toArray();
        return implode(' ', $js);
    }
}

ReactServiceProvider.php

namespace React;
use Illuminate\Support\Facades\Blade;
use Illuminate\Support\ServiceProvider;
class ReactServiceProvider extends ServiceProvider
{
    public function boot()
    {
        Blade::directive('css', function ($expression) {
            return "<?php echo app('" . ReactBladeDirective::class . "')->css($expression); ?>";
        });
        Blade::directive('js', function ($expression) {
            return "<?php echo app('" . ReactBladeDirective::class . "')->js($expression); ?>";
        });
    }
}