From 68c404b06e02b7559e1878095a4d6128dae7a6cc Mon Sep 17 00:00:00 2001
From: typer <teiqeo@gmail.com>
Date: Thu, 10 Sep 2020 19:58:48 -0700
Subject: [PATCH 1/2] fixed time drift by using a self-adjusting timer. no more
 imprecise timing!

---
 public/js/script.js | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/public/js/script.js b/public/js/script.js
index d8bb2a5e3..fe3432353 100644
--- a/public/js/script.js
+++ b/public/js/script.js
@@ -6,7 +6,7 @@ let correctedHistory = [];
 let currentCorrected = "";
 let currentInput = "";
 let time = 0;
-let timers = [];
+let timer = null;
 let testActive = false;
 let testStart, testEnd;
 let wpmHistory = [];
@@ -1633,7 +1633,7 @@ function showResult(difficultyFailed = false) {
       correctSpaces: 0,
     };
   }
-  clearIntervals();
+  clearTimeout(timer);
   let testtime = stats.time;
   let afkseconds = keypressPerSecond.filter((x) => x.count == 0).length;
   let afkSecondsPercent = roundTo2((afkseconds / testtime) * 100);
@@ -2314,6 +2314,8 @@ function startTest() {
   }
   testActive = true;
   testStart = Date.now();
+  const stepIntervalMS = 1000;
+  const expectedStepEnd = testStart + stepIntervalMS;
   // if (config.mode == "time") {
   restartTimer();
   showTimer();
@@ -2322,7 +2324,7 @@ function startTest() {
   // }
   // updateActiveElement();
   updateTimer();
-  clearIntervals();
+  clearTimeout(timer);
   keypressStats = {
     spacing: {
       current: -1,
@@ -2333,8 +2335,10 @@ function startTest() {
       array: [],
     },
   };
-  timers.push(
-    setInterval(function () {
+  //use a recursive self-adjusting timer to avoid time drift
+  (function loop(expectedStepEnd) {
+    const delay = expectedStepEnd - Date.now();
+    timer = setTimeout(function () {
       time++;
       if (config.mode === "time") {
         updateTimer();
@@ -2412,16 +2416,18 @@ function startTest() {
       if (config.mode == "time") {
         if (time >= config.time) {
           //times up
-          clearIntervals();
+          clearTimeout(timer);
           hideCaret();
           testActive = false;
           inputHistory.push(currentInput);
           correctedHistory.push(currentCorrected);
           showResult();
+          return;
         }
       }
-    }, 1000)
-  );
+      loop(expectedStepEnd + stepIntervalMS);
+    }, delay);
+  })(testStart + stepIntervalMS);
 }
 
 function restartTest(withSameWordset = false) {
@@ -2447,7 +2453,7 @@ function restartTest(withSameWordset = false) {
   }
 
   manualRestart = false;
-  clearIntervals();
+  clearTimeout(timer);
   time = 0;
   // afkDetected = false;
   wpmHistory = [];
@@ -2588,7 +2594,7 @@ function restartTest(withSameWordset = false) {
           125,
           () => {
             hideCrown();
-            clearIntervals();
+            clearTimeout(timer);
             $("#restartTestButton").css("opacity", 1);
             if ($("#commandLineWrapper").hasClass("hidden")) focusWords();
             wpmOverTimeChart.options.annotation.annotations[0].value = "-30";
@@ -2903,12 +2909,6 @@ function swapElements(
   }
 }
 
-function clearIntervals() {
-  timers.forEach((timer) => {
-    clearInterval(timer);
-  });
-}
-
 function updateAccountLoginButton() {
   if (firebase.auth().currentUser != null) {
     swapElements(

From 374fbdfd9a72cccae0ff33357e7a0e8cdd3fdc2f Mon Sep 17 00:00:00 2001
From: typer <teiqeo@gmail.com>
Date: Thu, 10 Sep 2020 22:59:35 -0700
Subject: [PATCH 2/2] cleaned up a couple lines

---
 public/js/script.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/public/js/script.js b/public/js/script.js
index fe3432353..0117a0cc0 100644
--- a/public/js/script.js
+++ b/public/js/script.js
@@ -2314,8 +2314,6 @@ function startTest() {
   }
   testActive = true;
   testStart = Date.now();
-  const stepIntervalMS = 1000;
-  const expectedStepEnd = testStart + stepIntervalMS;
   // if (config.mode == "time") {
   restartTimer();
   showTimer();
@@ -2336,6 +2334,7 @@ function startTest() {
     },
   };
   //use a recursive self-adjusting timer to avoid time drift
+  const stepIntervalMS = 1000;
   (function loop(expectedStepEnd) {
     const delay = expectedStepEnd - Date.now();
     timer = setTimeout(function () {