override __ function

app/functions.php

@@ -0,0 +1,40 @@
+<?php
+
+use Illuminate\Support\Facades\File;
+
+if (! function_exists('__')) {
+  /**
+   * Translate the given message.
+   *
+   * @param  string|null  $key
+   * @param  array  $replace
+   * @param  string|null  $locale
+   * @return string|array|null
+   */
+  function __($key = null, $replace = [], $locale = null)
+  {
+    $allDefinedTranslation = function () {
+      $path = lang_path(app()->getLocale() . '.json');
+      
+      return File::exists($path) ? json_decode(File::get($path), true) : [];
+    };
+
+    if (is_null($key)) {
+      return $key;
+    }
+
+    if (is_string($key)) {
+      $all = $allDefinedTranslation();
+
+      if (!array_key_exists($key, $all)) {
+        $all[$key] = $key;
+
+        $path = lang_path(app()->getLocale() . '.json');
+
+        File::put($path, json_encode($all, JSON_PRETTY_PRINT));
+      }
+    }
+
+    return trans($key, $replace, $locale);
+  }
+}

public/index.php

@@ -20,6 +20,8 @@ if (file_exists($maintenance = __DIR__.'/../storage/framework/maintenance.php'))
     require $maintenance;
 }
 
+require __DIR__ . '/../app/functions.php';
+
 /*
 |--------------------------------------------------------------------------
 | Register The Auto Loader