impr(burst-history): Use end time when calculating burst if test ended (@Leonabcd123) (#7302)

### Description

Use the time when test ended to calculate burst instead of current time,
so that burst history matches more closely actual wpm .

Example bug fixed:

When typing a single letter, wpm will be infinity but burst history will
be ~90.

---------

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

Author: Leonabcd123

frontend/src/ts/test/test-logic.ts

@@ -904,7 +904,7 @@ export async function finish(difficultyFailed = false): Promise<void> {
 
   //need one more calculation for the last word if test auto ended
   if (TestInput.burstHistory.length !== TestInput.input.getHistory()?.length) {
-    const burst = TestStats.calculateBurst();
+    const burst = TestStats.calculateBurst(now);
     TestInput.pushBurstToHistory(burst);
   }
 

frontend/src/ts/test/test-stats.ts

@@ -217,9 +217,9 @@ export function setLastSecondNotRound(): void {
   lastSecondNotRound = true;
 }
 
-export function calculateBurst(): number {
+export function calculateBurst(endTime: number = performance.now()): number {
   const containsKorean = TestInput.input.getKoreanStatus();
-  const timeToWrite = (performance.now() - TestInput.currentBurstStart) / 1000;
+  const timeToWrite = (endTime - TestInput.currentBurstStart) / 1000;
   let wordLength: number;
   wordLength = !containsKorean
     ? TestInput.input.current.length

frontend/src/ts/test/test-ui.ts

@@ -1436,8 +1436,7 @@ export async function applyBurstHeatmap(): Promise<void> {
 
     let burstlist = [...TestInput.burstHistory];
 
-    burstlist = burstlist.filter((x) => x !== Infinity);
-    burstlist = burstlist.filter((x) => x < 500);
+    burstlist = burstlist.map((x) => (x >= 1000 ? Infinity : x));
 
     const typingSpeedUnit = getTypingSpeedUnit(Config.typingSpeedUnit);
     burstlist.forEach((burst, index) => {
@@ -1508,7 +1507,7 @@ export async function applyBurstHeatmap(): Promise<void> {
       }
 
       $("#resultWordsHistory .heatmapLegend .box" + index).html(
-        `<div>${string}</div>`,
+        `<div>${Misc.escapeHTML(string)}</div>`,
       );
     });
 
@@ -1977,7 +1976,7 @@ $(".pageTest #resultWordsHistory").on("mouseenter", ".words .word", (e) => {
             .replace(/>/g, "&gt")}
           </div>
           <div class="speed">
-          ${Format.typingSpeed(burst, { showDecimalPlaces: false })}
+          ${isNaN(burst) || burst >= 1000 ? "Infinite" : Format.typingSpeed(burst, { showDecimalPlaces: false })}
           ${Config.typingSpeedUnit}
           </div>
           </div>`,