From 182da6a047b411150ebf351766013fb85b6cbcd3 Mon Sep 17 00:00:00 2001
From: Matthew Grove <me@mgrove.uk>
Date: Sat, 27 Nov 2021 16:44:33 +0000
Subject: [PATCH] Make processAnswer more efficient Insert into array at random
 index instead of randomising whole array

---
 functions/index.js | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/functions/index.js b/functions/index.js
index 3a87344..55349b3 100644
--- a/functions/index.js
+++ b/functions/index.js
@@ -634,11 +634,20 @@ exports.processAnswer = functions.https.onCall((data, context) => {
 
 					returnData.progress = ++docData.progress;
 					docData.incorrect.push(currentVocab);
-					docData.questions.push(currentVocab);
-					const doneQuestions = docData.questions.slice(0, docData.progress);
-					const notDoneQuestions = docData.questions.slice(docData.progress);
 					docData.current_correct = [];
-					docData.questions = doneQuestions.concat(shuffleArray(notDoneQuestions));
+					if (docData.questions.length > docData.progress) {
+						docData.questions.splice(
+							Math.floor(
+								Math.random() * (
+									docData.questions.length - docData.progress
+								)
+							) + docData.progress + 1,
+							0,
+							currentVocab
+						);
+					} else {
+					docData.questions.push(currentVocab);
+					}
 					returnData.totalQuestions = docData.questions.length;
 					returnData.totalIncorrect = docData.incorrect.length;