Fixed surveyjs/private-tasks#366 - KO: Survey doesn't have title and …

…description if loaded via SurveyID (#7819)

Co-authored-by: tsv2013 <[email protected]>

src/survey.ts

@@ -1023,6 +1023,8 @@ export class SurveyModel extends SurveyElementCore
       component: "sv-action-bar",
       data: this.navigationBar
     });
+
+    this.locTitle.onStringChanged.add(() => this.titleIsEmpty = this.locTitle.isEmpty);
   }
   processClosedPopup(question: IQuestion, popupModel: PopupModel<any>): void {
     throw new Error("Method not implemented.");
@@ -2084,9 +2086,10 @@ export class SurveyModel extends SurveyElementCore
     return new CssClassBuilder().append(this.css.logo)
       .append(logoClasses[this.logoPosition]).toString();
   }
+  @property({ defaultValue: true }) private titleIsEmpty: boolean;
   public get renderedHasTitle(): boolean {
     if (this.isDesignMode) return this.isPropertyVisible("title");
-    return !this.locTitle.isEmpty && this.showTitle;
+    return !this.titleIsEmpty && this.showTitle;
   }
   public get renderedHasDescription(): boolean {
     if (this.isDesignMode) return this.isPropertyVisible("description");
@@ -6113,6 +6116,7 @@ export class SurveyModel extends SurveyElementCore
     this.updateRenderBackgroundImage();
     this.updateCurrentPage();
     this.hasDescription = !!this.description;
+    this.titleIsEmpty = this.locTitle.isEmpty;
     this.setCalculatedWidthModeUpdater();
   }
 

tests/surveytests.ts

@@ -12428,6 +12428,7 @@ QUnit.test("Survey<=Base propertyValueChanged", function (assert) {
   var survey = new SurveyModel(json);
   var counter = 0;
 
+  let log = "";
   survey.onPropertyValueChangedCallback = (
     name: string,
     oldValue: any,
@@ -12436,13 +12437,14 @@ QUnit.test("Survey<=Base propertyValueChanged", function (assert) {
     arrayChanges: ArrayChanges
   ) => {
     counter++;
+    log += "->" + name;
   };
 
   assert.equal(counter, 0, "initial");
 
   survey.title = "new";
-
   assert.equal(counter, 1, "callback called");
+  assert.equal(log, "->title", "callback called for title");
 });
 
 QUnit.test(
@@ -15020,13 +15022,23 @@ QUnit.test("Test survey renderedHasTitle/renderedHasLogo properties", function (
   assert
 ) {
   var survey = new SurveyModel();
+  assert.equal(
+    survey["titleIsEmpty"],
+    true,
+    "titleIsEmpty due to no title"
+  );
   assert.equal(
     survey.renderedHasHeader,
     false,
     "hasHeader, title and logo are invisible"
   );
   assert.equal(survey.renderedHasTitle, false, "There is not title");
   survey.title = "title";
+  assert.equal(
+    survey["titleIsEmpty"],
+    false,
+    "titleIs not Empty due to title has been set"
+  );
   assert.equal(survey.renderedHasTitle, true, "There is title");
   assert.equal(survey.renderedHasHeader, true, "hasHeader, title is visible");
   survey.showTitle = false;