feat: new timeZone prop (experimental)

README.md

@@ -9,7 +9,7 @@ DayPicker is a [React](https://react.dev) component for creating date pickers, c
 - 🛠 Extensive set of props for [customizing](./docs/customization.mdx) the calendar.
 - 🎨 Minimal design that can be [easily styled](./docs/styling.mdx) with CSS or any CSS framework.
 - 📅 Supports [selections](./docs/selection-modes.mdx) of single days, multiple days, ranges of days, or [custom selections](./guides/custom-selections.mdx).
-- 🌍 Can be [localized](./docs/localization.mdx) into any language, supports [ISO 8601 dates](./docs/localization.mdx#iso-week-dates), [UTC dates](./docs/localization.mdx#utc-dates), and the [Jalali calendar](./docs/localization.mdx#jalali-calendar).
+- 🌍 Can be [localized](./docs/localization.mdx) into any language, supports [ISO 8601 dates](./docs/localization.mdx#iso-week-dates), [time zones](./docs/localization.mdx#time-zone), and the [Jalali calendar](./docs/localization.mdx#jalali-calendar).
 - 🦮 Complies with WCAG 2.1 AA requirements for [accessibility](./docs/accessibility.mdx).
 - ⚙️ [Customizable components](./guides/custom-components.mdx) to extend the rendered elements.
 - 🔤 Easy integration [with input fields](./guides/input-fields.mdx).

examples/TimeZone.tsx

@@ -0,0 +1,19 @@
+import React, { useState } from "react";
+
+import { DayPicker, TZDate } from "react-day-picker";
+
+export function TimeZone() {
+  const timezone = "Pacific/Kiritimati";
+  const [selected, setSelected] = useState<Date | undefined>(
+    TZDate.tz(timezone)
+  );
+  return (
+    <DayPicker
+      mode="single"
+      timeZone={timezone}
+      selected={selected}
+      onSelect={setSelected}
+      footer={selected ? `Selected: ${selected}` : "Pick a day."}
+    />
+  );
+}

examples/index.ts

@@ -65,6 +65,7 @@ export * from "./TailwindCSS";
 export * from "./Testcase1567";
 export * from "./TestCase2047";
 export * from "./TestCase2389";
+export * from "./TimeZone";
 export * from "./Utc";
 export * from "./WeekIso";
 export * from "./Weeknumber";

package.json

@@ -130,7 +130,8 @@
     "tsconfig.json"
   ],
   "dependencies": {
-    "date-fns": "^4.1.0"
+    "date-fns": "^4.1.0",
+    "@date-fns/tz": "^1.0.2"
   },
   "devDependencies": {
     "@date-fns/utc": "^2.1.0",

src/DayPicker.tsx

@@ -144,8 +144,15 @@ export function DayPicker(props: DayPickerProps) {
   } = labels;
 
   const weekdays = useMemo(
-    () => getWeekdays(locale, props.weekStartsOn, props.ISOWeek, dateLib),
-    [dateLib, locale, props.ISOWeek, props.weekStartsOn]
+    () =>
+      getWeekdays(
+        locale,
+        props.weekStartsOn,
+        props.ISOWeek,
+        props.timeZone,
+        dateLib
+      ),
+    [dateLib, locale, props.ISOWeek, props.timeZone, props.weekStartsOn]
   );
 
   const isInteractive = mode !== undefined || onDayClick !== undefined;

src/helpers/getDates.ts

@@ -9,7 +9,7 @@ export function getDates(
   maxDate: Date | undefined,
   props: Pick<
     DayPickerProps,
-    "ISOWeek" | "fixedWeeks" | "locale" | "weekStartsOn"
+    "ISOWeek" | "fixedWeeks" | "locale" | "weekStartsOn" | "timeZone"
   >,
   dateLib: DateLib
 ): Date[] {
@@ -53,7 +53,7 @@ export function getDates(
     if (maxDate && isAfter(date, maxDate)) {
       break;
     }
-    dates.push(new Date(date));
+    dates.push(date);
   }
 
   // If fixed weeks is enabled, add the extra dates to the array

src/helpers/getInitialMonth.ts

@@ -1,3 +1,5 @@
+import { TZDate } from "@date-fns/tz";
+
 import type { DateLib, DayPickerProps } from "../index.js";
 
 /** Return the start month based on the props passed to DayPicker. */
@@ -12,13 +14,14 @@ export function getInitialMonth(
     | "defaultMonth"
     | "today"
     | "numberOfMonths"
+    | "timeZone"
   >,
   dateLib: DateLib
 ): Date {
   const {
     month,
     defaultMonth,
-    today = new dateLib.Date(),
+    today = props.timeZone ? TZDate.tz(props.timeZone) : new dateLib.Date(),
     numberOfMonths = 1,
     endMonth,
     startMonth

src/helpers/getMonths.ts

@@ -16,6 +16,7 @@ export function getMonths(
     | "weekStartsOn"
     | "reverseMonths"
     | "firstWeekContainsDate"
+    | "timeZone"
   >,
   dateLib: DateLib
 ): CalendarMonth[] {

src/helpers/getNavMonth.ts

@@ -1,3 +1,5 @@
+import { TZDate } from "@date-fns/tz";
+
 import type { DateLib, DayPickerProps } from "../types/index.js";
 
 /** Return the start and end months for the calendar navigation. */
@@ -8,6 +10,7 @@ export function getNavMonths(
     | "endMonth"
     | "startMonth"
     | "today"
+    | "timeZone"
     // Deprecated:
     | "fromMonth"
     | "fromYear"
@@ -49,14 +52,20 @@ export function getNavMonths(
   } else if (fromYear) {
     startMonth = new Date(fromYear, 0, 1);
   } else if (!startMonth && hasDropdowns) {
-    startMonth = startOfYear(addYears(props.today ?? new Date(), -100));
+    const today =
+      props.today ??
+      (props.timeZone ? TZDate.tz(props.timeZone) : new dateLib.Date());
+    startMonth = startOfYear(addYears(today, -100));
   }
   if (endMonth) {
     endMonth = endOfMonth(endMonth);
   } else if (toYear) {
     endMonth = new Date(toYear, 11, 31);
   } else if (!endMonth && hasDropdowns) {
-    endMonth = endOfYear(props.today ?? new Date());
+    const today =
+      props.today ??
+      (props.timeZone ? TZDate.tz(props.timeZone) : new dateLib.Date());
+    endMonth = endOfYear(today);
   }
   return [
     startMonth ? startOfDay(startMonth) : startMonth,

src/helpers/getNextFocus.tsx

@@ -18,7 +18,13 @@ export function getNextFocus(
   calendarEndMonth: Date | undefined,
   props: Pick<
     DayPickerProps,
-    "disabled" | "hidden" | "modifiers" | "locale" | "ISOWeek" | "weekStartsOn"
+    | "disabled"
+    | "hidden"
+    | "modifiers"
+    | "locale"
+    | "ISOWeek"
+    | "weekStartsOn"
+    | "timeZone"
   >,
   dateLib: DateLib,
   attempt: number = 0

src/helpers/getWeekdays.test.ts

@@ -32,7 +32,7 @@ describe.each<0 | 1 | 2 | 3 | 4 | 5 | 6>([0, 1, 2, 3, 4, 5, 6])(
 
 describe("when using ISO week", () => {
   beforeEach(() => {
-    result = getWeekdays(es, 3, true, dateLib);
+    result = getWeekdays(es, 3, true, undefined, dateLib);
   });
   test("should return Monday as first day", () => {
     expect(result[0]).toBeMonday();

src/helpers/getWeekdays.ts

@@ -1,3 +1,5 @@
+import { TZDate } from "@date-fns/tz";
+
 import type { Locale } from "../lib/dateLib.js";
 import { dateLib as defaultDateLib } from "../lib/index.js";
 import type { DateLib } from "../types/index.js";
@@ -12,12 +14,14 @@ export function getWeekdays(
   weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | undefined,
   /** Use ISOWeek instead of locale/ */
   ISOWeek?: boolean | undefined,
+  timeZone?: string | undefined,
   /** @ignore */
   dateLib: DateLib = defaultDateLib
 ): Date[] {
+  const date = timeZone ? TZDate.tz(timeZone) : new dateLib.Date();
   const start = ISOWeek
-    ? dateLib.startOfISOWeek(new dateLib.Date())
-    : dateLib.startOfWeek(new dateLib.Date(), { locale, weekStartsOn });
+    ? dateLib.startOfISOWeek(date)
+    : dateLib.startOfWeek(date, { locale, weekStartsOn });
 
   const days = [];
   for (let i = 0; i < 7; i++) {

src/lib/dateLib.ts

@@ -51,7 +51,7 @@ export type { Month as DateFnsMonth } from "date-fns";
  */
 export const dateLib = {
   /** The constructor of the date object. */
-  Date: Date as GenericDateConstructor,
+  Date: Date as GenericDateConstructor<Date>,
   addDays,
   addMonths,
   addWeeks,

src/lib/index.ts

@@ -1 +1,2 @@
 export * from "./dateLib.js";
+export { TZDate } from "@date-fns/tz";

src/types/props.ts

@@ -256,6 +256,21 @@ export interface PropsBase {
    * @see https://en.wikipedia.org/wiki/ISO_week_date
    */
   ISOWeek?: boolean;
+  /**
+   * The time zone (IANA or UTC offset) to use in the calendar (experimental).
+   * See
+   * [Wikipedia](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)
+   * for the possible values.
+   *
+   * Time zones are supported by the `TZDate` object by the
+   * [@date-fns/tz](https://github.com/date-fns/tz) package. Please refer to the
+   * package documentation for more information.
+   *
+   * @since 9.1.1
+   * @experimental
+   * @see https://daypicker.dev/docs/localization#time-zone
+   */
+  timeZone?: string | undefined;
   /**
    * Change the components used for rendering the calendar elements.
    *

src/useCalendar.ts

@@ -1,3 +1,5 @@
+import { useEffect } from "react";
+
 import type {
   CalendarWeek,
   CalendarDay,
@@ -79,6 +81,7 @@ export function useCalendar(
     | "onMonthChange"
     | "month"
     | "defaultMonth"
+    | "timeZone"
     // Deprecated:
     | "fromMonth"
     | "fromYear"
@@ -90,14 +93,18 @@ export function useCalendar(
   const [navStart, navEnd] = getNavMonths(props, dateLib);
 
   const { startOfMonth, endOfMonth } = dateLib;
-
   const initialMonth = getInitialMonth(props, dateLib);
-
   const [firstMonth, setFirstMonth] = useControlledValue(
     initialMonth,
     props.month ? startOfMonth(props.month) : undefined
   );
 
+  useEffect(() => {
+    const newInitialMonth = getInitialMonth(props, dateLib);
+    setFirstMonth(newInitialMonth);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [props.timeZone]);
+
   /** The months displayed in the calendar. */
   const displayMonths = getDisplayMonths(firstMonth, navEnd, props, dateLib);
 

src/useGetModifiers.tsx

@@ -1,3 +1,5 @@
+import { TZDate } from "@date-fns/tz";
+
 import { DayFlag, SelectionState } from "./UI.js";
 import { CalendarDay } from "./classes/index.js";
 import type { DateLib, DayPickerProps, Modifiers } from "./types/index.js";
@@ -15,7 +17,7 @@ export function useGetModifiers(
 ) {
   const { disabled, hidden, modifiers, showOutsideDays, today } = props;
 
-  const { isSameDay, isSameMonth, Date } = dateLib;
+  const { isSameDay, isSameMonth } = dateLib;
 
   const internalModifiersMap: Record<DayFlag, CalendarDay[]> = {
     [DayFlag.focused]: [],
@@ -47,7 +49,10 @@ export function useGetModifiers(
       Boolean(hidden && dateMatchModifiers(date, hidden, dateLib)) ||
       (!showOutsideDays && isOutside);
 
-    const isToday = isSameDay(date, today ?? new Date());
+    const isToday = isSameDay(
+      date,
+      today ?? (props.timeZone ? TZDate.tz(props.timeZone) : new dateLib.Date())
+    );
 
     if (isOutside) internalModifiersMap.outside.push(day);
     if (isDisabled) internalModifiersMap.disabled.push(day);

src/utc.tsx

@@ -1,12 +1,10 @@
 import React from "react";
 
-import { UTCDate } from "@date-fns/utc";
-
 import {
   DayPicker as DayPickerComponent,
   type DayPickerProps
 } from "./index.js";
 
 export function DayPicker(props: DayPickerProps) {
-  return <DayPickerComponent dateLib={{ Date: UTCDate }} {...props} />;
+  return <DayPickerComponent timeZone="utc" {...props} />;
 }