Refactor frontend date formatting helpers and mark Task 10 done

frontend/src/components/BanTable.tsx

@@ -27,6 +27,7 @@ import {
 import { PageEmpty, PageError, PageLoading } from "./PageFeedback";
 import { ChevronLeftRegular, ChevronRightRegular } from "@fluentui/react-icons";
 import { useBans } from "../hooks/useBans";
+import { formatTimestamp } from "../utils/formatDate";
 import type { DashboardBanItem, TimeRange, BanOriginFilter } from "../types/ban";
 
 // ---------------------------------------------------------------------------
@@ -90,31 +91,6 @@ const useStyles = makeStyles({
   },
 });
 
-// ---------------------------------------------------------------------------
-// Helpers
-// ---------------------------------------------------------------------------
-
-/**
- * Format an ISO 8601 timestamp for display.
- *
- * @param iso - ISO 8601 UTC string.
- * @returns Localised date+time string.
- */
-function formatTimestamp(iso: string): string {
-  try {
-    return new Date(iso).toLocaleString(undefined, {
-      year: "numeric",
-      month: "2-digit",
-      day: "2-digit",
-      hour: "2-digit",
-      minute: "2-digit",
-      second: "2-digit",
-    });
-  } catch {
-    return iso;
-  }
-}
-
 // ---------------------------------------------------------------------------
 // Column definitions
 // ---------------------------------------------------------------------------

frontend/src/components/jail/BannedIpsSection.tsx

@@ -32,6 +32,7 @@ import {
   type TableColumnDefinition,
   createTableColumn,
 } from "@fluentui/react-components";
+import { formatTimestamp } from "../../utils/formatDate";
 import {
   ArrowClockwiseRegular,
   ChevronLeftRegular,
@@ -126,31 +127,6 @@ const useStyles = makeStyles({
   },
 });
 
-// ---------------------------------------------------------------------------
-// Helpers
-// ---------------------------------------------------------------------------
-
-/**
- * Format an ISO 8601 timestamp for compact display.
- *
- * @param iso - ISO 8601 string or `null`.
- * @returns A locale time string, or `"—"` when `null`.
- */
-function fmtTime(iso: string | null): string {
-  if (!iso) return "—";
-  try {
-    return new Date(iso).toLocaleString(undefined, {
-      year: "numeric",
-      month: "2-digit",
-      day: "2-digit",
-      hour: "2-digit",
-      minute: "2-digit",
-    });
-  } catch {
-    return iso;
-  }
-}
-
 // ---------------------------------------------------------------------------
 // Column definitions
 // ---------------------------------------------------------------------------
@@ -191,12 +167,16 @@ const columns: TableColumnDefinition<BanRow>[] = [
   createTableColumn<BanRow>({
     columnId: "banned_at",
     renderHeaderCell: () => "Banned At",
-    renderCell: ({ ban }) => <Text size={200}>{fmtTime(ban.banned_at)}</Text>,
+    renderCell: ({ ban }) => (
+      <Text size={200}>{ban.banned_at ? formatTimestamp(ban.banned_at) : "—"}</Text>
+    ),
   }),
   createTableColumn<BanRow>({
     columnId: "expires_at",
     renderHeaderCell: () => "Expires At",
-    renderCell: ({ ban }) => <Text size={200}>{fmtTime(ban.expires_at)}</Text>,
+    renderCell: ({ ban }) => (
+      <Text size={200}>{ban.expires_at ? formatTimestamp(ban.expires_at) : "—"}</Text>
+    ),
   }),
   createTableColumn<BanRow>({
     columnId: "actions",

frontend/src/pages/JailDetailPage.tsx

@@ -34,6 +34,7 @@ import {
 } from "@fluentui/react-icons";
 import { Link, useNavigate, useParams } from "react-router-dom";
 import { useJailDetail, useJailBannedIps } from "../hooks/useJails";
+import { formatSeconds } from "../utils/formatDate";
 import type { Jail } from "../types/jail";
 import { BannedIpsSection } from "../components/jail/BannedIpsSection";
 
@@ -146,16 +147,9 @@ const useStyles = makeStyles({
 });
 
 // ---------------------------------------------------------------------------
-// Helpers
+// Components
 // ---------------------------------------------------------------------------
 
-function fmtSeconds(s: number): string {
-  if (s < 0) return "permanent";
-  if (s < 60) return `${String(s)} s`;
-  if (s < 3600) return `${String(Math.round(s / 60))} min`;
-  return `${String(Math.round(s / 3600))} h`;
-}
-
 function CodeList({ items, empty }: { items: string[]; empty: string }): React.JSX.Element {
   const styles = useStyles();
   if (items.length === 0) {
@@ -313,9 +307,9 @@ function JailInfoSection({ jail, onRefresh, onStart, onStop, onSetIdle, onReload
         <Text className={styles.label}>Backend:</Text>
         <Text className={styles.mono}>{jail.backend}</Text>
         <Text className={styles.label}>Find time:</Text>
-        <Text>{fmtSeconds(jail.find_time)}</Text>
+        <Text>{formatSeconds(jail.find_time)}</Text>
         <Text className={styles.label}>Ban time:</Text>
-        <Text>{fmtSeconds(jail.ban_time)}</Text>
+        <Text>{formatSeconds(jail.ban_time)}</Text>
         <Text className={styles.label}>Max retry:</Text>
         <Text>{String(jail.max_retry)}</Text>
         {jail.date_pattern && (
@@ -413,13 +407,13 @@ function BantimeEscalationSection({ jail }: { jail: Jail }): React.JSX.Element |
         {esc.max_time !== null && (
           <>
             <Text className={styles.label}>Max time:</Text>
-            <Text>{fmtSeconds(esc.max_time)}</Text>
+            <Text>{formatSeconds(esc.max_time)}</Text>
           </>
         )}
         {esc.rnd_time !== null && (
           <>
             <Text className={styles.label}>Random jitter:</Text>
-            <Text>{fmtSeconds(esc.rnd_time)}</Text>
+            <Text>{formatSeconds(esc.rnd_time)}</Text>
           </>
         )}
         <Text className={styles.label}>Count across all jails:</Text>

frontend/src/pages/JailsPage.tsx

@@ -10,6 +10,7 @@
  */
 
 import { useState } from "react";
+import { formatSeconds } from "../utils/formatDate";
 import {
   Badge,
   Button,
@@ -140,17 +141,6 @@ const useStyles = makeStyles({
   lookupLabel: { fontWeight: tokens.fontWeightSemibold },
 });
 
-// ---------------------------------------------------------------------------
-// Helpers
-// ---------------------------------------------------------------------------
-
-function fmtSeconds(s: number): string {
-  if (s < 0) return "permanent";
-  if (s < 60) return `${String(s)}s`;
-  if (s < 3600) return `${String(Math.round(s / 60))}m`;
-  return `${String(Math.round(s / 3600))}h`;
-}
-
 // ---------------------------------------------------------------------------
 // Jail overview columns
 // ---------------------------------------------------------------------------
@@ -198,12 +188,12 @@ const jailColumns: TableColumnDefinition<JailSummary>[] = [
   createTableColumn<JailSummary>({
     columnId: "findTime",
     renderHeaderCell: () => "Find Time",
-    renderCell: (j) => <Text size={200}>{fmtSeconds(j.find_time)}</Text>,
+    renderCell: (j) => <Text size={200}>{formatSeconds(j.find_time)}</Text>,
   }),
   createTableColumn<JailSummary>({
     columnId: "banTime",
     renderHeaderCell: () => "Ban Time",
-    renderCell: (j) => <Text size={200}>{fmtSeconds(j.ban_time)}</Text>,
+    renderCell: (j) => <Text size={200}>{formatSeconds(j.ban_time)}</Text>,
   }),
   createTableColumn<JailSummary>({
     columnId: "maxRetry",

frontend/src/utils/formatDate.ts

@@ -130,3 +130,34 @@ export function formatRelative(
     return formatDate(isoUtc, timezone);
   }
 }
+
+/**
+ * Format an ISO 8601 timestamp for display with local browser timezone.
+ *
+ * Keeps parity with existing code paths in the UI that render full date+time
+ * strings inside table rows.
+ */
+export function formatTimestamp(iso: string): string {
+  try {
+    return new Date(iso).toLocaleString(undefined, {
+      year: "numeric",
+      month: "2-digit",
+      day: "2-digit",
+      hour: "2-digit",
+      minute: "2-digit",
+      second: "2-digit",
+    });
+  } catch {
+    return iso;
+  }
+}
+
+/**
+ * Format a duration in seconds to a compact text representation.
+ */
+export function formatSeconds(seconds: number): string {
+  if (seconds < 0) return "permanent";
+  if (seconds < 60) return `${String(seconds)} s`;
+  if (seconds < 3600) return `${String(Math.round(seconds / 60))} min`;
+  return `${String(Math.round(seconds / 3600))} h`;
+}