wip: inform window opener that module content is awaited

mon-pix/app/components/module/preview.gjs

@@ -1,12 +1,12 @@
 import PixButtonLink from '@1024pix/pix-ui/components/pix-button-link';
 import PixTextarea from '@1024pix/pix-ui/components/pix-textarea';
-import { on } from '@ember/modifier';
-import { action } from '@ember/object';
-import { service } from '@ember/service';
+import {on} from '@ember/modifier';
+import {action} from '@ember/object';
+import {service} from '@ember/service';
 import Component from '@glimmer/component';
-import { tracked } from '@glimmer/tracking';
-import { t } from 'ember-intl';
-import { pageTitle } from 'ember-page-title';
+import {tracked} from '@glimmer/tracking';
+import {t} from 'ember-intl';
+import {pageTitle} from 'ember-page-title';
 import ModulixGrain from 'mon-pix/components/module/grain';
 
 export default class ModulixPreview extends Component {
@@ -54,7 +54,7 @@ export default class ModulixPreview extends Component {
           "element": {
             "id": "3333333a-3333-3bcd-e333-3f3333gh3333",
             "type": "text",
-            "content": "<p>Voici un texte de leçon. Parfois, il y a des émojis pour aider à la lecture&nbsp;<span aria-hidden='true'>📚</span>.<br>Et là, voici une image&#8239;!</p>"
+            "content": "<p>Voici un texte de leçon. Parfois, il y a des émojis pour aider à la lecture&nbsp;<span aria-hidden="true">📚</span>.<br>Et là, voici une image&#8239;!</p>"
           }
         },
         {
@@ -78,11 +78,14 @@ export default class ModulixPreview extends Component {
 
     this.modulixPreviewMode.enable();
 
-    window.addEventListener('message', () => {
-      if (event.data?.from === 'modulix-editor') {
-        this.module = JSON.stringify(event.data.moduleContent, null, 2);
-      }
-    });
+    if(window.opener) {
+      window.addEventListener('message', (event) => {
+        if (event.data?.from === 'modulix-editor') {
+          this.module = JSON.stringify(event.data.moduleContent, null, 2);
+        }
+      });
+      window.opener.postMessage({from:'pix-app', message: 'Gimme the content !'}, '*');
+    }
   }
 
   get passage() {