Add mix file for loading versioned mix files.

src/Illuminate/Foundation/helpers.php

@@ -548,6 +548,45 @@ function method_field($method)
     }
 }
 
+if (! function_exists('mix')) {
+    /**
+     * Get the path to a versioned Mix file.
+     *
+     * @param  string  $path
+     * @return \Illuminate\Support\HtmlString
+     *
+     * @throws \InvalidArgumentException
+     */
+    function mix($path)
+    {
+        static $manifest;
+        static $shouldHotReload;
+
+        if (! $manifest) {
+            if (! file_exists($manifestPath = public_path('mix-manifest.json'))) {
+                throw new Exception('The Mix manifest does not exist.');
+            }
+
+            $manifest = json_decode(file_get_contents($manifestPath), true);
+        }
+
+        if (! starts_with($path, '/')) {
+            $path = "/{$path}";
+        }
+
+        if (! array_key_exists($path, $manifest)) {
+            throw new Exception(
+                "Unable to locate Mix file: {$path}. Please check your ".
+                "webpack.mix.js output paths and try again."
+            );
+        }
+
+        return $shouldHotReload = file_exists(public_path('hot'))
+                    ? new HtmlString("http://localhost:8080{$manifest[$path]}")
+                    : new HtmlString(url($manifest[$path]));
+    }
+}
+
 if (! function_exists('old')) {
     /**
      * Retrieve an old input item.