From cdaf9b2f2b8393d644f91ec964f5caf3aef774cc Mon Sep 17 00:00:00 2001
From: OlgaLarina <olga.larina.dev@gmail.com>
Date: Mon, 2 Dec 2024 15:51:55 +0300
Subject: [PATCH] resolve #9111 Dropdown with Lazy Loading - A list of items
 display duplicate entries

---
 packages/survey-core/src/dropdownListModel.ts | 12 ++--
 .../tests/questionDropdownTests.ts            | 57 +++++++++++++++++++
 2 files changed, 65 insertions(+), 4 deletions(-)

diff --git a/packages/survey-core/src/dropdownListModel.ts b/packages/survey-core/src/dropdownListModel.ts
index 95bf748c98..9ea4070f24 100644
--- a/packages/survey-core/src/dropdownListModel.ts
+++ b/packages/survey-core/src/dropdownListModel.ts
@@ -78,11 +78,8 @@ export class DropdownListModel extends Base {
     const isUpdate = (this.itemsSettings.skip + 1) < this.itemsSettings.totalCount;
     if (!this.itemsSettings.skip || isUpdate) {
 
+      this.resetTimer();
       if (!!this.filterString && settings.dropdownSearchDelay > 0) {
-        if (!!this.timer) {
-          clearTimeout(this.timer);
-          this.timer = undefined;
-        }
         this.timer = setTimeout(() => {
           this.loadQuestionChoices(callbackAfterItemsLoaded);
         }, settings.dropdownSearchDelay);
@@ -92,6 +89,13 @@ export class DropdownListModel extends Base {
     }
   }
 
+  private resetTimer(): void {
+    if (!!this.timer) {
+      clearTimeout(this.timer);
+      this.timer = undefined;
+    }
+  }
+
   private updatePopupFocusFirstInputSelector() {
     this._popupModel.focusFirstInputSelector = this.focusFirstInputSelector;
   }
diff --git a/packages/survey-core/tests/questionDropdownTests.ts b/packages/survey-core/tests/questionDropdownTests.ts
index 00cdd60b79..d9b077df43 100644
--- a/packages/survey-core/tests/questionDropdownTests.ts
+++ b/packages/survey-core/tests/questionDropdownTests.ts
@@ -2118,4 +2118,61 @@ QUnit.test("Rapidly Changing Search Filter", (assert) => {
     }, callbackTimeOutDelta);
     done1();
   }, callbackTimeOutDelta);
+});
+
+QUnit.test("Dropdown with Lazy Loading - A list of items display duplicate entries #9111", assert => {
+  const done1 = assert.async();
+  const done2 = assert.async();
+  const done3 = assert.async();
+  const done4 = assert.async();
+  const newValueDebouncedInputValue = onChoicesLazyLoadCallbackTimeOut;
+  const oldValueDebouncedInputValue = settings.dropdownSearchDelay;
+  settings.dropdownSearchDelay = newValueDebouncedInputValue;
+
+  const json = {
+    questions: [{ "type": "dropdown", "name": "q1", "choicesLazyLoadEnabled": true }]
+  };
+  const survey = new SurveyModel(json);
+  survey.onChoicesLazyLoad.add((_, opt) => {
+    setTimeout(() => {
+      opt.setItems(getNumberArray(0, 5, opt.filter), 5);
+    }, onChoicesLazyLoadCallbackTimeOut);
+  });
+
+  const question = <QuestionDropdownModel>survey.getAllQuestions()[0];
+  const itemsSettings = question.dropdownListModel["itemsSettings"];
+
+  assert.equal(question.choicesLazyLoadEnabled, true);
+  assert.equal(question.choices.length, 0);
+  assert.equal(question.choices.length, 0, "question.choices.length #1");
+  assert.equal(itemsSettings.items.length, 0, "itemsSettings.items.length #1");
+
+  question.dropdownListModel.popupModel.show();
+  setTimeout(() => {
+    assert.equal(question.choices.length, 5, "question.choices.length #2");
+
+    question.dropdownListModel.filterString = "22";
+    setTimeout(() => {
+      assert.equal(question.choices.length, 5, "question.choices.length #3");
+
+      question.dropdownListModel.filterString = "2";
+      setTimeout(() => {
+        assert.equal(question.choices.length, 5, "question.choices.length #4");
+
+        question.dropdownListModel.filterString = "";
+        setTimeout(() => {
+          assert.equal(question.choices.length, 5, "question.choices.length #5");
+
+          settings.dropdownSearchDelay = oldValueDebouncedInputValue;
+          done4();
+        }, onChoicesLazyLoadCallbackTimeOut + newValueDebouncedInputValue + callbackTimeOutDelta);
+
+        done3();
+      }, callbackTimeOutDelta);
+
+      done2();
+    }, onChoicesLazyLoadCallbackTimeOut + newValueDebouncedInputValue + callbackTimeOutDelta);
+
+    done1();
+  }, onChoicesLazyLoadCallbackTimeOut + newValueDebouncedInputValue + callbackTimeOutDelta);
 });
\ No newline at end of file