fix 1 case

src/components/animated-score.stories.js

@@ -42,3 +42,32 @@ export function Demo() {
     </div>
   );
 }
+
+export function OneCase() {
+  const {
+    nRequests,
+    nReviews,
+    now,
+    onStartAnim,
+    onStopAnim,
+    dateFirstActivity
+  } = useAnimatedScore(actions.slice(0, 1));
+
+  return (
+    <div
+      onMouseEnter={onStartAnim}
+      onMouseLeave={onStopAnim}
+      style={{ display: 'flex', alignItems: 'center' }}
+    >
+      <ScoreBadge
+        now={now}
+        nRequests={nRequests}
+        nReviews={nReviews}
+        dateFirstActivity={dateFirstActivity}
+      />
+      <span style={{ marginLeft: '4px' }}>
+        reviews {nReviews} + requests {nRequests}
+      </span>
+    </div>
+  );
+}

src/hooks/score-hooks.js

@@ -1,5 +1,9 @@
 import { useMemo, useState, useEffect, useCallback } from 'react';
 
+/**
+ * Note actions should always have a length of at least 1 as only preprint
+ * with reviews or requests for reviews are listed
+ */
 export function useAnimatedScore(actions) {
   const sorted = useMemo(() => {
     return actions.slice().sort((a, b) => {
@@ -17,13 +21,19 @@ export function useAnimatedScore(actions) {
       const tmax = new Date(sorted[sorted.length - 1].startTime).getTime();
 
       const t = new Date(sorted[Math.max(index, 0)].startTime).getTime();
-      const nextT = new Date(
-        sorted[Math.max(index + 1, 0)].startTime
-      ).getTime();
 
-      const rT = ((t - tmin) / (tmax - tmin)) * totalAnimTime;
-      const rNextT = ((nextT - tmin) / (tmax - tmin)) * totalAnimTime;
-      const timeout = rNextT - rT;
+      let timeout;
+      if (sorted.length > 1) {
+        const nextT = new Date(
+          sorted[Math.max(index + 1, 0)].startTime
+        ).getTime();
+
+        const rT = ((t - tmin) / (tmax - tmin)) * totalAnimTime;
+        const rNextT = ((nextT - tmin) / (tmax - tmin)) * totalAnimTime;
+        timeout = rNextT - rT;
+      } else {
+        timeout = totalAnimTime;
+      }
 
       const timeoutId = setTimeout(() => {
         setIndex(index + 1);
@@ -59,14 +69,14 @@ export function useAnimatedScore(actions) {
     index === null
       ? undefined
       : index === -1
-      ? sorted[0].startTime
+      ? sorted[0] && sorted[0].startTime
       : sorted[index].startTime;
 
   return {
     nRequests,
     nReviews,
     now,
-    dateFirstActivity: sorted[0].startTime,
+    dateFirstActivity: sorted[0] && sorted[0].startTime,
     onStartAnim: handleStartAnim,
     onStopAnim: handleStopAnim
   };