feat(datetime): ionChange will only emit from user committed changes (#26083)

resolves #20873 resolves #24452

BREAKING CHANGE

- `ionChange` is no longer emitted when the `value` property of `ion-datetime` is modified externally. `ionChange` is only emitted from user committed changes, such as clicking or tapping a date.

- Datetime no longer automatically adjusts the `value` property when passed an array and `multiple="false"`. Developers should update their apps to ensure they are using the API correctly.

BREAKING.md

@@ -16,6 +16,7 @@ This is a comprehensive list of the breaking changes introduced in the major ver
 - [Components](#version-7x-components)
   - [Accordion Group](#version-7x-accordion-group)
   - [Checkbox](#version-7x-checkbox)
+  - [Datetime](#version-7x-datetime)
   - [Input](#version-7x-input)
   - [Modal](#version-7x-modal)
   - [Overlays](#version-7x-overlays)
@@ -72,6 +73,12 @@ This section details the desktop browser, JavaScript framework, and mobile platf
 
 `ionChange` is no longer emitted when the `checked` property of `ion-checkbox` is modified externally. `ionChange` is only emitted from user committed changes, such as clicking or tapping the checkbox.
 
+<h4 id="version-7x-datetime">Datetime</h4>
+
+- `ionChange` is no longer emitted when the `value` property of `ion-datetime` is modified externally. `ionChange` is only emitted from user committed changes, such as clicking or tapping a date.
+
+- Datetime no longer automatically adjusts the `value` property when passed an array and `multiple="false"`. Developers should update their apps to ensure they are using the API correctly.
+
 <h4 id="version-7x-input">Input</h4>
 
 - `ionChange` is no longer emitted when the `value` of `ion-input` is modified externally. `ionChange` is only emitted from user committed changes, such as typing in the input and the input losing focus or from clicking the clear action within the input.

angular/test/base/e2e/src/inputs.spec.ts

@@ -44,7 +44,8 @@ describe('Inputs', () => {
     cy.get('ion-input').eq(0).type('hola');
     cy.get('ion-input input').eq(0).blur();
 
-    cy.get('ion-datetime').invoke('prop', 'value', '1996-03-15');
+    // Set date to 1994-03-14
+    cy.get('ion-datetime').first().shadow().find('.calendar-day:not([disabled])').first().click();
 
     cy.get('ion-select#game-console').click();
     cy.get('ion-alert').should('exist').should('be.visible');
@@ -58,7 +59,7 @@ describe('Inputs', () => {
     cy.get('#checkbox-note').should('have.text', 'true');
     cy.get('#toggle-note').should('have.text', 'true');
     cy.get('#input-note').should('have.text', 'hola');
-    cy.get('#datetime-note').should('have.text', '1996-03-15');
+    cy.get('#datetime-note').should('have.text', '1994-03-14');
     cy.get('#select-note').should('have.text', 'ps');
     cy.get('#range-note').should('have.text', '20');
   });

core/src/components.d.ts

@@ -845,7 +845,7 @@ export namespace Components {
          */
         "titleSelectedDatesFormatter"?: TitleSelectedDatesFormatter;
         /**
-          * The value of the datetime as a valid ISO 8601 datetime string. Should be an array of strings if `multiple="true"`.
+          * The value of the datetime as a valid ISO 8601 datetime string. This should be an array of strings only when `multiple="true"`.
          */
         "value"?: string | string[] | null;
         /**
@@ -4588,6 +4588,10 @@ declare namespace LocalJSX {
           * Emitted when the styles change.
          */
         "onIonStyle"?: (event: IonDatetimeCustomEvent<StyleEventDetail>) => void;
+        /**
+          * Emitted when the value property has changed. This is used to ensure that ion-datetime-button can respond to any value property changes.
+         */
+        "onIonValueChange"?: (event: IonDatetimeCustomEvent<DatetimeChangeEventDetail>) => void;
         /**
           * If `true`, a wheel picker will be rendered instead of a calendar grid where possible. If `false`, a calendar grid will be rendered instead of a wheel picker where possible.  A wheel picker can be rendered instead of a grid when `presentation` is one of the following values: `'date'`, `'date-time'`, or `'time-date'`.  A wheel picker will always be rendered regardless of the `preferWheel` value when `presentation` is one of the following values: `'time'`, `'month'`, `'month-year'`, or `'year'`.
          */
@@ -4625,7 +4629,7 @@ declare namespace LocalJSX {
          */
         "titleSelectedDatesFormatter"?: TitleSelectedDatesFormatter;
         /**
-          * The value of the datetime as a valid ISO 8601 datetime string. Should be an array of strings if `multiple="true"`.
+          * The value of the datetime as a valid ISO 8601 datetime string. This should be an array of strings only when `multiple="true"`.
          */
         "value"?: string | string[] | null;
         /**

core/src/components/datetime-button/datetime-button.tsx

@@ -126,7 +126,7 @@ export class DatetimeButton implements ComponentInterface {
        * text in the buttons.
        */
       this.setDateTimeText();
-      addEventListener(datetimeEl, 'ionChange', this.setDateTimeText);
+      addEventListener(datetimeEl, 'ionValueChange', this.setDateTimeText);
 
       /**
        * Configure the initial selected button

core/src/components/datetime-button/test/multiple/datetime-button.e2e.ts

@@ -73,12 +73,12 @@ test.describe('datetime-button: multiple selection', () => {
     await page.waitForSelector('.datetime-ready');
 
     const datetime = page.locator('ion-datetime');
-    const ionChange = await page.spyOnEvent('ionChange');
+    const ionValueChange = await page.spyOnEvent('ionValueChange');
     const dateButton = page.locator('#date-button');
     await expect(dateButton).toHaveText('2 days');
 
     await datetime.evaluate((el: HTMLIonDatetimeElement) => (el.value = ['2022-06-01', '2022-06-02', '2022-06-03']));
-    await ionChange.next();
+    await ionValueChange.next();
 
     await expect(dateButton).toHaveText('3 days');
   });

core/src/components/datetime/datetime.tsx

@@ -321,7 +321,7 @@ export class Datetime implements ComponentInterface {
 
   /**
    * The value of the datetime as a valid ISO 8601 datetime string.
-   * Should be an array of strings if `multiple="true"`.
+   * This should be an array of strings only when `multiple="true"`.
    */
   @Prop({ mutable: true }) value?: string | string[] | null;
 
@@ -330,13 +330,10 @@ export class Datetime implements ComponentInterface {
    */
   @Watch('value')
   protected valueChanged() {
-    const { value, minParts, maxParts, workingParts, multiple } = this;
+    const { value, minParts, maxParts, workingParts } = this;
 
     if (this.hasValue()) {
-      if (!multiple && Array.isArray(value)) {
+      this.warnIfIncorrectValueUsage();
-        this.value = value[0];
-        return; // setting this.value will trigger re-run of this function
-      }
 
       /**
        * Clones the value of the `activeParts` to the private clone, to update
@@ -383,7 +380,7 @@ export class Datetime implements ComponentInterface {
     }
 
     this.emitStyle();
-    this.ionChange.emit({ value });
+    this.ionValueChange.emit({ value });
   }
 
   /**
@@ -459,6 +456,14 @@ export class Datetime implements ComponentInterface {
    */
   @Event() ionChange!: EventEmitter<DatetimeChangeEventDetail>;
 
+  /**
+   * Emitted when the value property has changed.
+   * This is used to ensure that ion-datetime-button can respond
+   * to any value property changes.
+   * @internal
+   */
+  @Event() ionValueChange!: EventEmitter<DatetimeChangeEventDetail>;
+
   /**
    * Emitted when the datetime has focus.
    */
@@ -496,7 +501,7 @@ export class Datetime implements ComponentInterface {
     if (activeParts !== undefined || !isCalendarPicker) {
       const activePartsIsArray = Array.isArray(activeParts);
       if (activePartsIsArray && activeParts.length === 0) {
-        this.value = undefined;
+        this.setValue(undefined);
       } else {
         /**
          * Prevent convertDataToISO from doing any
@@ -517,7 +522,7 @@ export class Datetime implements ComponentInterface {
           activeParts.tzOffset = date.getTimezoneOffset() * -1;
         }
 
-        this.value = convertDataToISO(activeParts);
+        this.setValue(convertDataToISO(activeParts));
       }
     }
 
@@ -551,6 +556,32 @@ export class Datetime implements ComponentInterface {
     }
   }
 
+  private warnIfIncorrectValueUsage = () => {
+    const { multiple, value } = this;
+    if (!multiple && Array.isArray(value)) {
+      /**
+       * We do some processing on the `value` array so
+       * that it looks more like an array when logged to
+       * the console.
+       * Example given ['a', 'b']
+       * Default toString() behavior: a,b
+       * Custom behavior: ['a', 'b']
+       */
+      printIonWarning(
+        `ion-datetime was passed an array of values, but multiple="false". This is incorrect usage and may result in unexpected behaviors. To dismiss this warning, pass a string to the "value" property when multiple="false".
+
+  Value Passed: [${value.map((v) => `'${v}'`).join(', ')}]
+`,
+        this.el
+      );
+    }
+  };
+
+  private setValue = (value?: string | string[] | null) => {
+    this.value = value;
+    this.ionChange.emit({ value });
+  };
+
   /**
    * Returns the DatetimePart interface
    * to use when rendering an initial set of
@@ -1155,13 +1186,11 @@ export class Datetime implements ComponentInterface {
 
   private processValue = (value?: string | string[] | null) => {
     const hasValue = value !== null && value !== undefined;
-    let valueToProcess = parseDate(value ?? getToday());
+    const valueToProcess = parseDate(value ?? getToday());
 
-    const { minParts, maxParts, multiple } = this;
+    const { minParts, maxParts } = this;
-    if (!multiple && Array.isArray(value)) {
+
-      this.value = value[0];
+    this.warnIfIncorrectValueUsage();
-      valueToProcess = (valueToProcess as DatetimeParts[])[0];
-    }
 
     /**
      * Datetime should only warn of out of bounds values
@@ -1319,7 +1348,7 @@ export class Datetime implements ComponentInterface {
 
     const clearButtonClick = () => {
       this.reset();
-      this.value = undefined;
+      this.setValue(undefined);
     };
 
     /**

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

@@ -279,3 +279,40 @@ test.describe('datetime: visibility', () => {
     await expect(monthYearInterface).toBeHidden();
   });
 });
+
+test.describe('datetime: ionChange', () => {
+  test.beforeEach(({ skip }) => {
+    skip.rtl();
+    skip.mode('ios', 'ionChange has consistent behavior across modes');
+  });
+
+  test('should fire ionChange when confirming a value from the calendar grid', async ({ page }) => {
+    await page.setContent(`
+      <ion-datetime presentation="date" value="2022-01-02"></ion-datetime>
+    `);
+
+    await page.waitForSelector('.datetime-ready');
+
+    const ionChange = await page.spyOnEvent('ionChange');
+    const calendarButtons = page.locator('.calendar-day:not([disabled])');
+
+    await calendarButtons.nth(0).click();
+
+    await ionChange.next();
+    await expect(ionChange).toHaveReceivedEventTimes(1);
+  });
+
+  test('should not fire ionChange when programmatically setting a value', async ({ page }) => {
+    await page.setContent(`
+      <ion-datetime presentation="date" value="2022-01-02"></ion-datetime>
+    `);
+
+    await page.waitForSelector('.datetime-ready');
+
+    const ionChange = await page.spyOnEvent('ionChange');
+    const datetime = page.locator('ion-datetime');
+
+    await datetime.evaluate((el: HTMLIonDatetimeElement) => (el.value = '2022-01-01'));
+    await expect(ionChange).not.toHaveReceivedEvent();
+  });
+});

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

@@ -93,11 +93,6 @@ test.describe('datetime: multiple date selection (functionality)', () => {
     await expect(monthYear).toHaveText('April 2022');
   });
 
-  test('multiple=false and array for defaulut value should switch to first item', async ({ page }) => {
-    const datetime = await setup(page, 'multipleFalseArrayValue');
-    await expect(datetime).toHaveJSProperty('value', '2022-06-01');
-  });
-
   test('with buttons, should only update value when confirm is called', async ({ page }) => {
     const datetime = await setup(page, 'withButtons');
     const june2Button = datetime.locator('[data-month="6"][data-day="2"]');

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

@@ -164,13 +164,10 @@ class TimePickerFixture {
   }
 
   async setValue(value: string) {
-    const ionChange = await this.page.spyOnEvent('ionChange');
     await this.timePicker.evaluate((el: HTMLIonDatetimeElement, newValue: string) => {
       el.value = newValue;
     }, value);
 
-    await ionChange.next();
-
     // Changing the value can take longer than the default 100ms to repaint
     await this.page.waitForChanges(300);
   }

packages/vue/src/proxies.ts

@@ -297,6 +297,7 @@ export const IonDatetime = /*@__PURE__*/ defineContainer<JSX.IonDatetime>('ion-d
   'preferWheel',
   'ionCancel',
   'ionChange',
+  'ionValueChange',
   'ionFocus',
   'ionBlur',
   'ionStyle',