ts: définit et utilise un typeguard pour vérifier la présence d'une propriété.

src/php/Resources/views/repositories.ts.twig

@@ -13,6 +13,11 @@ import { {% for name in repoImports %}
 {%- endfor %}
 } from './resources';
 
+// Simple type guard helper for object with keys
+function hasProperty<T extends string|number|symbol>(what: unknown, key: T): what is { [key in T]: any; } {
+    return typeof what === 'object' && what !== null && key in what;
+}
+
 /*********************************************************************************
  * Repositories
  *********************************************************************************/

src/php/TypescriptHelper.php

@@ -66,7 +66,7 @@ final class TypescriptHelper
      */
     public static function propertyTestor(string $object, string $name): string
     {
-        return sprintf('(%s in %s)', self::quoteString($name), $object);
+        return sprintf('hasProperty(%s, %s)', $object, self::quoteString($name));
     }
 
     /**