Add undefined check to avoid TS2532

src/ts/frontend.ts

@@ -226,7 +226,11 @@ function generateTables(rollstats: RollStats): void {
 		let tb = $("#outcomeTable").find("tbody");
 		let outcome: Outcomes = okeys[i] as Outcomes;
 		let outcomeCount = rollstats.outcomeCounts[outcome];
-		let outcomePercent = (outcomeCount / rollstats.numRolls * 100).toFixed(2);
+		let outcomePercent: string = "";
+		if (outcomeCount) {
+			// Needed to avoid TS2532:
+			outcomePercent = (outcomeCount / rollstats.numRolls * 100).toFixed(2);
+		}
 		tb.append(`<tr> <td>${outcome}</td>
 			  <td>${outcomeCount}</td>
 			  <td>${outcomePercent}</td>