fix: Education | Quiz accepting duplicate question #20622 (#20708)

diff --git a/erpnext/education/doctype/quiz/quiz.js b/erpnext/education/doctype/quiz/quiz.js
index 122cf37..7b87088 100644
--- a/erpnext/education/doctype/quiz/quiz.js
+++ b/erpnext/education/doctype/quiz/quiz.js
@@ -4,5 +4,18 @@
 frappe.ui.form.on('Quiz', {
 	refresh: function(frm) {
 
+	},
+	validate: function(frm){
+		frm.events.check_duplicate_question(frm.doc.question);
+	},
+	check_duplicate_question: function(questions_data){
+		var questions = [];
+		questions_data.forEach(function(q){
+			questions.push(q.question_link);
+		});
+		var questions_set = new Set(questions);
+		if (questions.length != questions_set.size) {
+			frappe.throw(__("The question cannot be duplicate"));
+		}
 	}
-});
+});
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