fix(calendar): validate date and time with Zod

Author: j15z

bun.lock

@@ -37,7 +37,8 @@
   "dependencies": {
     "@sim/utils": "workspace:*",
     "clsx": "^2.1.1",
-    "tailwind-merge": "3.6.0"
+    "tailwind-merge": "3.6.0",
+    "zod": "4.3.6"
   },
   "peerDependencies": {
     "@radix-ui/react-avatar": "^1.1.10",

packages/emcn/package.json

@@ -1,7 +1,7 @@
 /**
  * @vitest-environment node
  */
-import { describe, expect, it } from 'vitest'
+import { describe, expect, it, vi } from 'vitest'
 import {
   buildRangeBounds,
   formatDateRangeLabel,
@@ -20,13 +20,26 @@ describe('parseDateTimeValue', () => {
     expect(parseDateTimeValue('2026-07-06T16:04').time).toBe('16:04')
   })
 
-  it.each(['14:30:00.000001', '14:30:45.123456', '00:00:00.999999'])(
+  it.each(['14:30:00.000001', '14:30:45.123456', '00:00:00.999999', '14:30:45.123456789'])(
     'retains the full wall time %s for subsequent date selections',
     (time) => {
       expect(parseDateTimeValue(`2026-09-07T${time}`).time).toBe(time)
     }
   )
 
+  it.each([
+    ['2026-09-07T07:30:45.123456Z', '07:30:45'],
+    ['2026-09-07T07:30:45.123456-07:00', '14:30:45'],
+    ['2026-09-07T07:30:45.123456+05:45', '01:45:45'],
+  ])('keeps explicit-offset input %s on the instant conversion path', (value, expectedTime) => {
+    vi.stubEnv('TZ', 'UTC')
+    try {
+      expect(parseDateTimeValue(value).time).toBe(expectedTime)
+    } finally {
+      vi.unstubAllEnvs()
+    }
+  })
+
   it('does not reinterpret a literal wall time through a daylight-saving gap', () => {
     expect(parseDateTimeValue('2026-03-08T02:30:45.123456').time).toBe('02:30:45.123456')
   })

packages/emcn/src/components/calendar/calendar.test.ts

@@ -1,6 +1,7 @@
 'use client'
 
 import { useMemo, useState } from 'react'
+import { z } from 'zod'
 import { ChevronLeft, ChevronRight } from '../../icons'
 import { cn } from '../../lib/cn'
 import { Chip, chipVariants } from '../chip/chip'
@@ -27,6 +28,7 @@ const WEEKDAYS = ['Su', 'Mo', 'Tu', 'We', 'Th', 'Fr', 'Sa'] as const
 
 const DEFAULT_RANGE_START_TIME = '00:00'
 const DEFAULT_RANGE_END_TIME = '23:59'
+const localDateTimePartsSchema = z.tuple([z.iso.date(), z.iso.time()])
 
 function getDaysInMonth(year: number, month: number): number {
   return new Date(year, month + 1, 0).getDate()
@@ -155,10 +157,9 @@ export function parseDateTimeValue(value: string | Date | undefined): {
   const parsed = value instanceof Date ? value : new Date(value)
   if (Number.isNaN(parsed.getTime())) return { date: null, time: null }
   if (typeof value === 'string') {
-    const wallTime =
-      /^\d{4}-\d{2}-\d{2}T((?:[01]\d|2[0-3]):[0-5]\d(?::[0-5]\d(?:\.\d{1,9})?)?)$/.exec(value)
-    if (wallTime) {
-      const time = wallTime[1]
+    const wallTime = localDateTimePartsSchema.safeParse(value.split('T'))
+    if (wallTime.success) {
+      const [, time] = wallTime.data
       return {
         date: parsed,
         time: time.length === 8 && time.endsWith(':00') ? time.slice(0, 5) : time,