Show singular 'update' in notification when there's only one

src/shared/pluralize.ts

+/**
+ * Naive simple English pluralization
+ */
+export function pluralize(count: number, singular: string, plural: string) {
+  return count === 1 ? singular : plural;
+}

src/shared/test/pluralize-test.js

+import { pluralize } from '../pluralize';
+
+describe('pluralize', () => {
+  [
+    { count: 0, expectedResult: 'people' },
+    { count: 1, expectedResult: 'person' },
+    { count: 2, expectedResult: 'people' },
+    { count: 10, expectedResult: 'people' },
+  ].forEach(({ count, expectedResult }) => {
+    it('returns expected form', () => {
+      assert.equal(pluralize(count, 'person', 'people'), expectedResult);
+    });
+  });
+});

src/sidebar/components/PendingUpdatesNotification.tsx

@@ -2,6 +2,7 @@ import { Button, DownloadIcon } from '@hypothesis/frontend-shared';
 import classnames from 'classnames';
 import { useCallback, useEffect, useRef, useState } from 'preact/hooks';
 
+import { pluralize } from '../../shared/pluralize';
 import { useShortcut } from '../../shared/shortcut';
 import { withServices } from '../service-context';
 import type { StreamerService } from '../services/streamer';
@@ -74,7 +75,8 @@ function PendingUpdatesNotification({
       >
         {!collapsed && (
           <span data-testid="full-notification" className="whitespace-nowrap">
-            Load <span className="font-bold">{pendingUpdateCount}</span> updates{' '}
+            Load <span className="font-bold">{pendingUpdateCount}</span>{' '}
+            {pluralize(pendingUpdateCount, 'update', 'updates')}{' '}
             <span className="sr-only">by pressing l</span>
           </span>
         )}

src/sidebar/components/ShareDialog/ExportAnnotations.tsx

@@ -9,6 +9,7 @@ import {
 import { useCallback, useId, useMemo, useState } from 'preact/hooks';
 
 import { downloadFile } from '../../../shared/download-file';
+import { pluralize } from '../../../shared/pluralize';
 import type { APIAnnotationData } from '../../../types/api';
 import { annotationDisplayName } from '../../helpers/annotation-user';
 import type { UserAnnotations } from '../../helpers/annotations-by-user';
@@ -256,11 +257,6 @@ function ExportAnnotations({
     return <LoadingSpinner />;
   }
 
-  // Naive simple English pluralization
-  const pluralize = (count: number, singular: string, plural: string) => {
-    return count === 1 ? singular : plural;
-  };
-
   return (
     <form
       className="space-y-3"

src/sidebar/components/SidebarTabs.tsx

@@ -9,6 +9,7 @@ import {
 import classnames from 'classnames';
 import type { ComponentChildren } from 'preact';
 
+import { pluralize } from '../../shared/pluralize';
 import type { SidebarSettings } from '../../types/config';
 import type { TabName } from '../../types/sidebar';
 import { applyTheme } from '../helpers/theme';
@@ -127,11 +128,6 @@ function SidebarTabs({
 
   const showNotesUnavailableMessage = selectedTab === 'note' && noteCount === 0;
 
-  // Naive simple English pluralization
-  const pluralize = (count: number, singular: string, plural: string) => {
-    return count === 1 ? singular : plural;
-  };
-
   const tabCountsSummaryPieces = [];
   if (annotationCount > 0) {
     const term = pluralize(annotationCount, 'annotation', 'annotations');