fix(angular): null values are not converted to falsy value (#26341)

BREAKING CHANGE:

Datetime:

Passing the empty string to the `value` property will now error as it is not a valid ISO-8601 value.

Angular:

`null` values on form components will no longer be converted to the empty string (`''`) or `false`. This impacts `ion-checkbox`, `ion-datetime`, `ion-input`, `ion-radio`, `ion-radio-group`, ion-range`, `ion-searchbar`, `ion-segment`, `ion-select`, `ion-textarea`, and `ion-toggle`.

BREAKING.md

@@ -35,6 +35,7 @@ This is a comprehensive list of the breaking changes introduced in the major ver
 - [Types](#version-7x-types)
   - [Overlay Attribute Interfaces](#version-7x-overlay-attribute-interfaces)
 - [JavaScript Frameworks](#version-7x-javascript-frameworks)
+  - [Angular](#version-7x-angular)
   - [React](#version-7x-react)
   - [Vue](#version-7x-vue)
 - [Utilities](#version-7x-utilities)
@@ -101,6 +102,8 @@ This section details the desktop browser, JavaScript framework, and mobile platf
 
 - Datetime no longer incorrectly reports the time zone when `value` is updated. Datetime does not manage time zones, so any time zone information provided is ignored.
 
+- Passing the empty string to the `value` property will now error as it is not a valid ISO-8601 value.
+
 <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.
@@ -223,6 +226,10 @@ Any references to the virtual scroll types from `@ionic/core` have been removed.
 
 <h2 id="version-7x-javascript-frameworks">JavaScript Frameworks</h2>
 
+<h4 id="version-7x-angular">Angular</h4>
+
+- `null` values on form components will no longer be converted to the empty string (`''`) or `false`. This impacts `ion-checkbox`, `ion-datetime`, `ion-input`, `ion-radio`, `ion-radio-group`, ion-range`, `ion-searchbar`, `ion-segment`, `ion-select`, `ion-textarea`, and `ion-toggle`.
+
 <h4 id="version-7x-react">React</h4>
 
 `@ionic/react` and `@ionic/react-router` no longer ship a CommonJS entry point. Instead, only an ES Module entry point is provided for improved compatibility with Vite.

angular/src/directives/control-value-accessors/boolean-value-accessor.ts

@@ -19,7 +19,7 @@ export class BooleanValueAccessorDirective extends ValueAccessor {
   }
 
   writeValue(value: any): void {
-    this.el.nativeElement.checked = this.lastValue = value == null ? false : value;
+    this.el.nativeElement.checked = this.lastValue = value;
     setIonicClasses(this.el);
   }
 

angular/src/directives/control-value-accessors/value-accessor.ts

@@ -18,14 +18,7 @@ export class ValueAccessor implements ControlValueAccessor, AfterViewInit, OnDes
   constructor(protected injector: Injector, protected el: ElementRef) {}
 
   writeValue(value: any): void {
-    /**
-     * TODO FW-2646
-     * Change `value == null ? '' : value;`
-     * to `value`. This was a fix for IE9, but IE9
-     * is no longer supported; however, this change
-     * is potentially a breaking change
-     */
-    this.el.nativeElement.value = this.lastValue = value == null ? '' : value;
+    this.el.nativeElement.value = this.lastValue = value;
     setIonicClasses(this.el);
   }
 

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

@@ -16,9 +16,15 @@ describe('Inputs', () => {
 
     cy.get('ion-checkbox').should('have.prop', 'checked').and('equal', false);
     cy.get('ion-toggle').should('have.prop', 'checked').and('equal', false);
-    cy.get('ion-input').should('have.prop', 'value').and('equal', '');
-    cy.get('ion-datetime').should('have.prop', 'value').and('equal', '');
-    cy.get('ion-select').should('have.prop', 'value').and('equal', '');
+    /**
+     * The `value` property gets set to undefined
+     * for these components, so we need to check
+     * not.have.prop which will check that the
+     * value property is undefined.
+     */
+    cy.get('ion-input').should('not.have.prop', 'value');
+    cy.get('ion-datetime').should('not.have.prop', 'value');
+    cy.get('ion-select').should('not.have.prop', 'value');
   });
 
   it('should get some value', () => {

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

@@ -160,8 +160,7 @@ export class DatetimeButton implements ComponentInterface {
    * to keep checking if the datetime value is `string` or `string[]`.
    */
   private getParsedDateValues = (value?: string[] | string | null): string[] => {
-    // TODO FW-2646 Remove value === ''
-    if (value === '' || value === undefined || value === null) {
+    if (value === undefined || value === null) {
       return [];
     }
 

core/src/components/datetime/datetime.tsx

@@ -1171,7 +1171,7 @@ export class Datetime implements ComponentInterface {
   }
 
   private processValue = (value?: string | string[] | null) => {
-    const hasValue = value !== '' && value !== null && value !== undefined;
+    const hasValue = value !== null && value !== undefined;
     const valueToProcess = hasValue ? parseDate(value) : this.defaultParts;
 
     const { minParts, maxParts } = this;
@@ -1283,7 +1283,7 @@ export class Datetime implements ComponentInterface {
   };
 
   private hasValue = () => {
-    return this.value != null && this.value !== '';
+    return this.value != null;
   };
 
   private nextMonth = () => {