🩹(react) harmonize date picker components output

By introducing this utility function, we ensure that any output value
is converted back to an ISO 8601 date and time string in UTC timezone.
Overall, it harmonize and factorize the way we output
values from date picker components.

.changeset/swift-forks-exercise.md

@@ -0,0 +1,5 @@
+---
+"@openfun/cunningham-react": patch
+---
+
+Fix datepicker component's output timezone management

packages/react/src/components/Forms/DatePicker/DatePicker.spec.tsx

@@ -1,16 +1,24 @@
 import userEvent from "@testing-library/user-event";
 import { render, screen, within } from "@testing-library/react";
 import React, { FormEvent, useState } from "react";
-import { afterEach, expect, vi } from "vitest";
+import { expect, vi } from "vitest";
 import { CunninghamProvider } from ":/components/Provider";
 import { DatePicker } from ":/components/Forms/DatePicker/DatePicker";
 import { Button } from ":/components/Button";
 
-describe("<DatePicker/>", () => {
-  afterEach(() => {
-    vi.restoreAllMocks();
-  });
+vi.mock("@internationalized/date", async () => {
+  const mod = await vi.importActual<typeof import("@internationalized/date")>(
+    "@internationalized/date"
+  );
+  return {
+    ...mod,
+    // Note: Restoring mocks will cause the function to return 'undefined'.
+    // Consider providing a default implementation to be restored instead.
+    getLocalTimeZone: vi.fn().mockReturnValue("Europe/Paris"),
+  };
+});
 
+describe("<DatePicker/>", () => {
   const expectCalendarToBeClosed = () => {
     expect(screen.queryByRole("application")).toBeNull();
   };
@@ -525,7 +533,7 @@ describe("<DatePicker/>", () => {
     expectCalendarToBeClosed();
 
     // Make sure value is selected.
-    screen.getByText(`Value = 2023-04-12|`);
+    screen.getByText(`Value = 2023-04-11T22:00:00.000Z|`);
 
     // Clear value.
     const clearButton = screen.getByRole("button", {
@@ -633,7 +641,7 @@ describe("<DatePicker/>", () => {
     expect(monthSegment).toHaveFocus();
 
     // Type date's value.
-    await user.keyboard("{1}{2}{5}{2}{0}{2}{3}");
+    await user.keyboard("{5}{1}{2}{2}{0}{2}{3}");
 
     // Submit form being filled with a date.
     await user.click(submitButton);
@@ -642,7 +650,7 @@ describe("<DatePicker/>", () => {
 
     // Make sure form's value matches.
     expect(formData).toEqual({
-      datepicker: "2023-12-05",
+      datepicker: "2023-05-11T22:00:00.000Z",
     });
 
     // Clear picked date.

packages/react/src/components/Forms/DatePicker/DatePicker.tsx

@@ -12,6 +12,7 @@ import { Calendar } from ":/components/Forms/DatePicker/Calendar";
 import DateFieldBox from ":/components/Forms/DatePicker/DateField";
 import { StringOrDate } from ":/components/Forms/DatePicker/types";
 import {
+  convertDateValueToString,
   getDefaultPickerOptions,
   parseCalendarDate,
 } from ":/components/Forms/DatePicker/utils";
@@ -41,7 +42,7 @@ export const DatePicker = (props: DatePickerProps) => {
         : parseCalendarDate(props.value),
     defaultValue: parseCalendarDate(props.defaultValue),
     onChange: (value: DateValue | null) => {
-      props.onChange?.(value?.toString() || "");
+      props.onChange?.(convertDateValueToString(value));
     },
   };
   const pickerState = useDatePickerState(options);

packages/react/src/components/Forms/DatePicker/DatePickerAux.tsx

@@ -21,6 +21,7 @@ import {
   Calendar,
   CalendarRange,
 } from ":/components/Forms/DatePicker/Calendar";
+import { convertDateValueToString } from ":/components/Forms/DatePicker/utils";
 
 export type DatePickerAuxSubProps = FieldProps & {
   label?: string;
@@ -111,19 +112,19 @@ const DatePickerAux = forwardRef(
                   <input
                     type="hidden"
                     name={name && `${name}_start`}
-                    value={pickerState.value?.start?.toString() || ""}
+                    value={convertDateValueToString(pickerState.value.start)}
                   />
                   <input
                     type="hidden"
                     name={name && `${name}_end`}
-                    value={pickerState.value?.end?.toString() || ""}
+                    value={convertDateValueToString(pickerState.value.end)}
                   />
                 </>
               ) : (
                 <input
                   type="hidden"
                   name={name}
-                  value={pickerState.value?.toString() || ""}
+                  value={convertDateValueToString(pickerState.value)}
                 />
               )}
               <div className="c__date-picker__wrapper__icon">

packages/react/src/components/Forms/DatePicker/DateRangePicker.spec.tsx

@@ -6,6 +6,18 @@ import { CunninghamProvider } from ":/components/Provider";
 import { DateRangePicker } from ":/components/Forms/DatePicker/DateRangePicker";
 import { Button } from ":/components/Button";
 
+vi.mock("@internationalized/date", async () => {
+  const mod = await vi.importActual<typeof import("@internationalized/date")>(
+    "@internationalized/date"
+  );
+  return {
+    ...mod,
+    // Note: Restoring mocks will cause the function to return 'undefined'.
+    // Consider providing a default implementation to be restored instead.
+    getLocalTimeZone: vi.fn().mockReturnValue("Europe/Paris"),
+  };
+});
+
 describe("<DateRangePicker/>", () => {
   const expectDatesToBeEqual = (
     firstDate: Date | string | undefined | null,
@@ -938,7 +950,9 @@ describe("<DateRangePicker/>", () => {
     expectCalendarToBeClosed();
 
     // Make sure value is selected.
-    screen.getByText(`Value = 2023-04-12 2023-04-14|`);
+    screen.getByText(
+      `Value = 2023-04-11T22:00:00.000Z 2023-04-13T22:00:00.000Z|`
+    );
 
     // Clear value.
     const clearButton = screen.getByRole("button", {
@@ -1004,10 +1018,10 @@ describe("<DateRangePicker/>", () => {
     expect(startMonthSegment).toHaveFocus();
 
     // Type start date's value.
-    await user.keyboard("{1}{0}{5}{2}{0}{2}{3}");
+    await user.keyboard("{5}{1}{0}{2}{0}{2}{3}");
 
     // Type end date's value.
-    await user.keyboard("{1}{2}{5}{2}{0}{2}{3}");
+    await user.keyboard("{5}{1}{2}{2}{0}{2}{3}");
 
     // Submit form being filled with a date.
     await user.click(submitButton);
@@ -1016,8 +1030,8 @@ describe("<DateRangePicker/>", () => {
 
     // Make sure form's value matches.
     expect(formData).toEqual({
-      datepickerStart: "2023-10-05",
-      datepickerEnd: "2023-12-05",
+      datepickerStart: "2023-05-09T22:00:00.000Z",
+      datepickerEnd: "2023-05-11T22:00:00.000Z",
     });
 
     // Clear picked date.

packages/react/src/components/Forms/DatePicker/DateRangePicker.tsx

@@ -12,6 +12,7 @@ import DatePickerAux, {
 import DateFieldBox from ":/components/Forms/DatePicker/DateField";
 import { StringsOrDateRange } from ":/components/Forms/DatePicker/types";
 import {
+  convertDateValueToString,
   getDefaultPickerOptions,
   parseRangeCalendarDate,
 } from ":/components/Forms/DatePicker/utils";
@@ -44,7 +45,10 @@ export const DateRangePicker = ({
     onChange: (value: DateRange) => {
       props.onChange?.(
         value?.start && value.end
-          ? [value.start.toString(), value.end.toString()]
+          ? [
+              convertDateValueToString(value.start),
+              convertDateValueToString(value.end),
+            ]
           : null,
       );
     },

packages/react/src/components/Forms/DatePicker/utils.spec.ts

@@ -1,5 +1,12 @@
-import { CalendarDate, DateValue, parseDate } from "@internationalized/date";
 import {
+  CalendarDate,
+  DateValue,
+  parseAbsolute,
+  parseDate,
+} from "@internationalized/date";
+import { vi } from "vitest";
+import {
+  convertDateValueToString,
   parseCalendarDate,
   parseRangeCalendarDate,
 } from ":/components/Forms/DatePicker/utils";
@@ -17,6 +24,18 @@ const expectDateToBeEqual = (
   expect(parsedDate?.day === expectedDay);
 };
 
+vi.mock("@internationalized/date", async () => {
+  const mod = await vi.importActual<typeof import("@internationalized/date")>(
+    "@internationalized/date",
+  );
+  return {
+    ...mod,
+    // Note: Restoring mocks will cause the function to return 'undefined'.
+    // Consider providing a default implementation to be restored instead.
+    getLocalTimeZone: vi.fn().mockReturnValue("Europe/Paris"),
+  };
+});
+
 describe("parseCalendarDate", () => {
   it.each([
     [2023, 4, 12],
@@ -161,3 +180,24 @@ describe("parseRangeCalendarDate", () => {
     expectDateToBeEqual(range?.end, 2023, 4, 22);
   });
 });
+
+describe("convertDateValueToString", () => {
+  it("should return an empty string for null date", () => {
+    const date: DateValue | null = null;
+    const result = convertDateValueToString(date);
+    expect(result).toBe("");
+  });
+
+  it("should return a UTC ISO 8601 string from a CalendarDate", async () => {
+    const date = parseDate("2023-05-25");
+    const result = convertDateValueToString(date);
+    expect(result).eq("2023-05-24T22:00:00.000Z");
+  });
+
+  it("should return a UTC ISO 8601 string from a ZonedDateTime", async () => {
+    // Europe/Paris is the mocked local timezone.
+    const date = parseAbsolute("2023-05-25T00:00:00.000+02:00", "Europe/Paris");
+    const result = convertDateValueToString(date);
+    expect(result).eq("2023-05-24T22:00:00.000Z");
+  });
+});

packages/react/src/components/Forms/DatePicker/utils.ts

@@ -1,7 +1,11 @@
 import {
   CalendarDate,
+  DateValue,
   parseAbsoluteToLocal,
   toCalendarDate,
+  ZonedDateTime,
+  toZoned,
+  getLocalTimeZone,
 } from "@internationalized/date";
 import { DateRange } from "react-aria";
 import {
@@ -38,6 +42,19 @@ export const parseRangeCalendarDate = (
   };
 };
 
+export const convertDateValueToString = (date: DateValue | null): string => {
+  try {
+    const localTimezone = getLocalTimeZone();
+    // If timezone is already set, it would be kept, else the selection is set at midnight
+    // on the local timezone, then converted to a UTC offset.
+    return date ? toZoned(date, localTimezone).toAbsoluteString() : "";
+  } catch (e) {
+    throw new Error(
+      "Invalid date format when converting date value on DatePicker component"
+    );
+  }
+};
+
 export const getDefaultPickerOptions = (props: DatePickerAuxSubProps): any => ({
   minValue: parseCalendarDate(props.minValue),
   maxValue: parseCalendarDate(props.maxValue),