AAE-35668 Sending empty string instead of null after clearing value from numeric field

lib/core/src/lib/form/components/widgets/number/number.widget.html

@@ -21,7 +21,7 @@
                    [required]="isRequired()"
                    [value]="displayValue"
                    [(ngModel)]="field.value"
-                   (ngModelChange)="onFieldChanged(field)"
+                   (ngModelChange)="onNumberChange($event)"
                    [disabled]="field.readOnly"
                    [placeholder]="field.placeholder"
                    [title]="field.tooltip"

lib/core/src/lib/form/components/widgets/number/number.widget.spec.ts

@@ -40,6 +40,45 @@ describe('NumberWidgetComponent', () => {
         testingUtils = new UnitTestingUtils(fixture.debugElement, loader);
     });
 
+    describe('with default value', () => {
+        beforeEach(() => {
+            widget.field = new FormFieldModel(new FormModel({ taskId: '<id>' }), {
+                type: FormFieldTypes.NUMBER,
+                value: 123,
+                id: 'number-id'
+            });
+            fixture.detectChanges();
+        });
+
+        it('should display the value', async () => {
+            const input = await testingUtils.getMatInput();
+
+            expect(await input.getValue()).toBe('123');
+            expect(widget.field.value).toBe(123);
+        });
+
+        it('should have value null when field is cleared', async () => {
+            const input = await testingUtils.getMatInput();
+            await input.setValue('');
+
+            expect(widget.field.value).toBeNull();
+        });
+
+        it('should have value null when value is undefined', async () => {
+            const input = await testingUtils.getMatInput();
+            await input.setValue(undefined);
+
+            expect(widget.field.value).toBeNull();
+        });
+
+        it('should have value null when value is null', async () => {
+            const input = await testingUtils.getMatInput();
+            await input.setValue(null);
+
+            expect(widget.field.value).toBeNull();
+        });
+    });
+
     describe('when tooltip is set', () => {
         beforeEach(() => {
             widget.field = new FormFieldModel(new FormModel({ taskId: '<id>' }), {

lib/core/src/lib/form/components/widgets/number/number.widget.ts

@@ -62,4 +62,12 @@ export class NumberWidgetComponent extends WidgetComponent implements OnInit {
             this.displayValue = this.field.value;
         }
     }
+
+    protected onNumberChange(value: string) {
+        if (value === null || value === undefined || value === '') {
+            this.field.value = null;
+        }
+
+        this.onFieldChanged(this.field);
+    }
 }