refactor: extract shared date formatting utilities in frontend

Three components had duplicate date formatting functions. Extract
formatDateChip (for detail/input views with optional time) and
formatDateLabel (for compact list items) to a shared dateFormat module.

https://claude.ai/code/session_013ooJht2HrZUTXgNJFU79cV

apps/tauri/src/lib/components/NewTaskInput.svelte

@@ -5,6 +5,7 @@
 
 <script lang="ts">
   import { app } from "../stores/app.svelte";
+  import { formatDateChip } from "../dateFormat";
   import DateTimePicker from "./DateTimePicker.svelte";
 
   let title = $state("");
@@ -41,16 +42,6 @@
     dateHasTime = hasTime;
   }
 
-  function formatDateChip(iso: string): string {
-    const d = new Date(iso);
-    const today = new Date();
-    const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
-    const day = dayNames[d.getDay()];
-    const pad = (n: number) => String(n).padStart(2, "0");
-    const timePart = dateHasTime ? `, ${pad(d.getHours())}:${pad(d.getMinutes())}` : "";
-    if (d.toDateString() === today.toDateString()) return `Today${timePart}`;
-    return `${day}, ${pad(d.getDate())}/${pad(d.getMonth() + 1)}${timePart}`;
-  }
 
   $effect(() => {
     if (newTaskState.open) {
@@ -105,7 +96,7 @@
       {#if date}
         <div class="flex items-center gap-1.5 rounded-full border border-border-light bg-black/5 px-3 py-1 text-sm dark:border-border-dark dark:bg-white/10">
           <button type="button" onclick={() => (showDatePicker = true)} class="hover:opacity-70">
-            {formatDateChip(date)}
+            {formatDateChip(date, dateHasTime)}
           </button>
           <button type="button" onclick={() => (date = null)} class="opacity-40 hover:opacity-80">
             <svg class="h-3.5 w-3.5" viewBox="0 0 20 20" fill="currentColor">

apps/tauri/src/lib/components/TaskDetailView.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
   import type { Task } from "../types";
   import { app } from "../stores/app.svelte";
+  import { formatDateChip } from "../dateFormat";
   import DateTimePicker from "./DateTimePicker.svelte";
   import ConfirmDialog from "./ConfirmDialog.svelte";
   import { getCurrentWindow } from "@tauri-apps/api/window";
@@ -118,17 +119,6 @@
     }
   });
 
-  function formatDateChip(iso: string): string {
-    const d = new Date(iso);
-    const today = new Date();
-    const dayNames = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
-    const day = dayNames[d.getDay()];
-    const pad = (n: number) => String(n).padStart(2, "0");
-    const hasTime = task.has_time;
-    const timePart = hasTime ? `, ${pad(d.getHours())}:${pad(d.getMinutes())}` : "";
-    if (d.toDateString() === today.toDateString()) return `Today${timePart}`;
-    return `${day}, ${pad(d.getDate())}/${pad(d.getMonth() + 1)}${timePart}`;
-  }
 </script>
 
 <!-- Header -->
@@ -240,7 +230,7 @@
     {#if task.date}
       <div class="flex items-center gap-1.5 rounded-full border border-border-light bg-black/5 px-3 py-1 text-sm dark:border-border-dark dark:bg-white/10">
         <button onclick={() => (showDatePicker = true)} class="hover:opacity-70">
-          {formatDateChip(task.date)}
+          {formatDateChip(task.date, task.has_time)}
         </button>
         <button onclick={() => handleDateChange(null)} class="opacity-40 hover:opacity-80">
           <svg class="h-3.5 w-3.5" viewBox="0 0 20 20" fill="currentColor">

apps/tauri/src/lib/components/TaskItem.svelte

@@ -5,6 +5,7 @@
 <script lang="ts">
   import type { Task } from "../types";
   import { app } from "../stores/app.svelte";
+  import { formatDateLabel } from "../dateFormat";
 
   let { task, onopen, depth = 0, dateChipStyle = "normal", showSubtaskCount = true }: { task: Task; onopen?: (task: Task) => void; depth?: number; dateChipStyle?: "normal" | "overdue" | "hidden"; showSubtaskCount?: boolean } = $props();
 
@@ -77,15 +78,6 @@
     swiping = false;
   }
 
-  function formatDate(iso: string): string {
-    const d = new Date(iso);
-    const today = new Date();
-    if (d.toDateString() === today.toDateString()) return "Today";
-    const tomorrow = new Date(today);
-    tomorrow.setDate(today.getDate() + 1);
-    if (d.toDateString() === tomorrow.toDateString()) return "Tomorrow";
-    return d.toLocaleDateString(undefined, { month: "short", day: "numeric" });
-  }
 </script>
 
 <div
@@ -153,11 +145,11 @@
       {#if task.date && dateChipStyle !== "hidden"}
         {#if dateChipStyle === "overdue"}
           <span class="mt-1 inline-block rounded-full border border-danger px-2 py-0.5 text-xs text-danger opacity-80">
-            {formatDate(task.date)}
+            {formatDateLabel(task.date)}
           </span>
         {:else}
           <span class="mt-1 inline-block rounded-full border border-border-light px-2 py-0.5 text-xs opacity-50 dark:border-border-dark">
-            {formatDate(task.date)}
+            {formatDateLabel(task.date)}
           </span>
         {/if}
       {/if}

apps/tauri/src/lib/dateFormat.ts

@@ -0,0 +1,23 @@
+const DAY_NAMES = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
+const pad = (n: number) => String(n).padStart(2, "0");
+
+/** Format a date for display in chips (detail view, new task input). */
+export function formatDateChip(iso: string, hasTime: boolean): string {
+  const d = new Date(iso);
+  const today = new Date();
+  const day = DAY_NAMES[d.getDay()];
+  const timePart = hasTime ? `, ${pad(d.getHours())}:${pad(d.getMinutes())}` : "";
+  if (d.toDateString() === today.toDateString()) return `Today${timePart}`;
+  return `${day}, ${pad(d.getDate())}/${pad(d.getMonth() + 1)}${timePart}`;
+}
+
+/** Format a date for compact display in task list items. */
+export function formatDateLabel(iso: string): string {
+  const d = new Date(iso);
+  const today = new Date();
+  if (d.toDateString() === today.toDateString()) return "Today";
+  const tomorrow = new Date(today);
+  tomorrow.setDate(today.getDate() + 1);
+  if (d.toDateString() === tomorrow.toDateString()) return "Tomorrow";
+  return d.toLocaleDateString(undefined, { month: "short", day: "numeric" });
+}