fix(datetime): reinit behavior on presentation change (#24828)

Co-authored-by: Sean Perkins <sean@ionic.io>

core/src/components/datetime/datetime.tsx

@@ -94,9 +94,13 @@ export class Datetime implements ComponentInterface {
 
   private destroyCalendarIO?: () => void;
   private destroyKeyboardMO?: () => void;
+  private destroyOverlayListener?: () => void;
 
   private minParts?: any;
   private maxParts?: any;
+  private todayParts = parseDate(getToday());
+
+  private prevPresentation: string | null = null;
 
   /**
    * Duplicate reference to `activeParts` that does not trigger a re-render of the component.
@@ -124,8 +128,6 @@ export class Datetime implements ComponentInterface {
     ampm: 'pm'
   }
 
-  private todayParts = parseDate(getToday())
-
   @Element() el!: HTMLIonDatetimeElement;
 
   @State() isPresented = false;
@@ -483,8 +485,18 @@ export class Datetime implements ComponentInterface {
     this.confirm();
   }
 
+  /**
+   * Stencil sometimes sets calendarBodyRef to null on rerender, even though
+   * the element is present. Query for it manually as a fallback.
+   *
+   * TODO(FW-901) Remove when issue is resolved: https://github.com/ionic-team/stencil/issues/3253
+   */
+  private getCalendarBodyEl = () => {
+    return this.calendarBodyRef || this.el.shadowRoot?.querySelector('.calendar-body');
+  };
+
   private initializeKeyboardListeners = () => {
-    const { calendarBodyRef } = this;
+    const calendarBodyRef = this.getCalendarBodyEl();
     if (!calendarBodyRef) { return; }
 
     const root = this.el!.shadowRoot!;
@@ -530,7 +542,7 @@ export class Datetime implements ComponentInterface {
      * We must use keydown not keyup as we want
      * to prevent scrolling when using the arrow keys.
      */
-    this.calendarBodyRef!.addEventListener('keydown', (ev: KeyboardEvent) => {
+    calendarBodyRef.addEventListener('keydown', (ev: KeyboardEvent) => {
       const activeElement = root.activeElement;
       if (!activeElement || !activeElement.classList.contains('calendar-day')) { return; }
 
@@ -657,7 +669,7 @@ export class Datetime implements ComponentInterface {
   }
 
   private initializeCalendarIOListeners = () => {
-    const { calendarBodyRef } = this;
+    const calendarBodyRef = this.getCalendarBodyEl();
     if (!calendarBodyRef) { return; }
 
     const mode = getIonMode(this);
@@ -873,7 +885,7 @@ export class Datetime implements ComponentInterface {
    * listener. This is so that we can re-create the listeners
    * if the datetime has been hidden/presented by a modal or popover.
    */
-  private destroyListeners = () => {
+  private destroyInteractionListeners = () => {
     const { destroyCalendarIO, destroyKeyboardMO } = this;
 
     if (destroyCalendarIO !== undefined) {
@@ -885,6 +897,12 @@ export class Datetime implements ComponentInterface {
     }
   }
 
+  private initializeListeners() {
+    this.initializeCalendarIOListeners();
+    this.initializeKeyboardListeners();
+    this.initializeOverlayListener();
+  }
+
   componentDidLoad() {
     /**
      * If a scrollable element is hidden using `display: none`,
@@ -898,9 +916,7 @@ export class Datetime implements ComponentInterface {
       const ev = entries[0];
       if (!ev.isIntersecting) { return; }
 
-      this.initializeCalendarIOListeners();
-      this.initializeKeyboardListeners();
-      this.initializeOverlayListener();
+      this.initializeListeners();
 
       /**
        * TODO: Datetime needs a frame to ensure that it
@@ -936,7 +952,7 @@ export class Datetime implements ComponentInterface {
       const ev = entries[0];
       if (ev.isIntersecting) { return; }
 
-      this.destroyListeners();
+      this.destroyInteractionListeners();
 
       writeTask(() => {
         this.el.classList.remove('datetime-ready');
@@ -959,6 +975,29 @@ export class Datetime implements ComponentInterface {
     root.addEventListener('ionBlur', (ev: Event) => ev.stopPropagation());
   }
 
+  /**
+   * When the presentation is changed, all calendar content is recreated,
+   * so we need to re-init behavior with the new elements.
+   */
+  componentDidRender() {
+    const { presentation, prevPresentation } = this;
+
+    if (prevPresentation === null) {
+      this.prevPresentation = presentation;
+      return;
+    }
+
+    if (presentation === prevPresentation) { return; }
+    this.prevPresentation = presentation;
+
+    this.destroyInteractionListeners();
+    if (this.destroyOverlayListener !== undefined) {
+      this.destroyOverlayListener();
+    }
+
+    this.initializeListeners();
+  }
+
   /**
    * When doing subsequent presentations of an inline
    * overlay, the IO callback will fire again causing
@@ -970,9 +1009,15 @@ export class Datetime implements ComponentInterface {
     const overlay = this.el.closest('ion-popover, ion-modal');
     if (overlay === null) { return; }
 
-    overlay.addEventListener('willPresent', () => {
+    const overlayListener = () => {
       this.overlayIsPresenting = true;
-    });
+    };
+
+    overlay.addEventListener('willPresent', overlayListener);
+
+    this.destroyOverlayListener = () => {
+      overlay.removeEventListener('willPresent', overlayListener);
+    };
   }
 
   private processValue = (value?: string | null) => {
@@ -1034,7 +1079,7 @@ export class Datetime implements ComponentInterface {
   }
 
   private nextMonth = () => {
-    const { calendarBodyRef } = this;
+    const calendarBodyRef = this.getCalendarBodyEl();
     if (!calendarBodyRef) { return; }
 
     const nextMonth = calendarBodyRef.querySelector('.calendar-month:last-of-type');
@@ -1050,7 +1095,7 @@ export class Datetime implements ComponentInterface {
   }
 
   private prevMonth = () => {
-    const { calendarBodyRef } = this;
+    const calendarBodyRef = this.getCalendarBodyEl();
     if (!calendarBodyRef) { return; }
 
     const prevMonth = calendarBodyRef.querySelector('.calendar-month:first-of-type');

core/src/components/datetime/test/display/e2e.ts

@@ -52,3 +52,41 @@ test('display', async () => {
     expect(screenshotCompare).toMatchScreenshot();
   }
 });
+
+test('month selection should work after changing presentation', async () => {
+  const page = await newE2EPage({
+    url: '/src/components/datetime/test/display?ionic:_testing=true'
+  });
+  const ionWorkingPartsDidChange = await page.spyOnEvent('ionWorkingPartsDidChange', 'document');
+  let calendarMonthYear;
+
+  await page.select('#presentation', 'date-time');
+  await page.waitForChanges();
+
+  await page.select('#presentation', 'time-date');
+  await page.waitForChanges();
+
+  const nextMonthButton = await page.find('ion-datetime >>> .calendar-next-prev ion-button + ion-button');
+  await nextMonthButton.click();
+  await page.waitForChanges();
+
+  await ionWorkingPartsDidChange.next();
+
+  calendarMonthYear = await page.find('ion-datetime >>> .calendar-month-year');
+
+  expect(calendarMonthYear.textContent).toContain('March 2022');
+
+  // ensure it still works if presentation is changed more than once
+  await page.select('#presentation', 'date-time');
+  await page.waitForChanges();
+
+  const prevMonthButton = await page.find('ion-datetime >>> .calendar-next-prev ion-button:first-child');
+  await prevMonthButton.click();
+  await page.waitForChanges();
+
+  await ionWorkingPartsDidChange.next();
+
+  calendarMonthYear = await page.find('ion-datetime >>> .calendar-month-year');
+
+  expect(calendarMonthYear.textContent).toContain('February 2022');
+});

core/src/components/datetime/test/display/index.html

@@ -1,10 +1,10 @@
 <!DOCTYPE html>
 <html lang="en" dir="ltr">
+
 <head>
   <meta charset="UTF-8">
   <title>Datetime - Standalone</title>
-    <meta name="viewport"
-      content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
   <link href="../../../../../css/ionic.bundle.css" rel="stylesheet">
   <link href="../../../../../scripts/testing/styles.css" rel="stylesheet">
   <script src="../../../../../scripts/testing/scripts.js"></script>
@@ -13,11 +13,13 @@
     body {
       padding: 20px;
     }
+
     ion-datetime {
       border: 1px solid black;
     }
   </style>
 </head>
+
 <body>
   <label for="presentation">Presentation</label>
   <select id="presentation" onchange="changePresentation(event)">
@@ -36,17 +38,43 @@
 
   <br /><br />
 
-    <ion-datetime></ion-datetime>
+  <ion-datetime value="2022-02-22"></ion-datetime>
 
   <script>
     const datetime = document.querySelector('ion-datetime');
 
-      const changePresentation = (ev) => {
-        datetime.presentation = ev.target.value;
+    const mutationObserver = new MutationObserver(() => {
+      document.dispatchEvent(new CustomEvent('ionWorkingPartsDidChange'));
+    });
+
+    const initCalendarMonthChangeObserver = async () => {
+      if (!datetime.componentOnReady) return;
+      await datetime.componentOnReady();
+      
+      // We have to requestAnimationFrame to allow the datetime to render completely.
+      requestAnimationFrame(() => {
+        const calendarBody = datetime.shadowRoot.querySelector('.calendar-body');
+        if (calendarBody) {
+          mutationObserver.observe(calendarBody, {
+            childList: true,
+            subtree: true
+          });
         }
+      });
+    }
+
+    const changePresentation = (ev) => {
+      mutationObserver.disconnect();
+      datetime.presentation = ev.target.value;
+      initCalendarMonthChangeObserver();
+    };
+
     const changeSize = (ev) => {
       datetime.size = ev.target.value;
-      }
+    };
+
+    initCalendarMonthChangeObserver();
   </script>
 </body>
+
 </html>