fix(forms): default to unsetValue for value accessors

nativescript-angular/forms/value-accessors/base-value-accessor.ts

@@ -1,5 +1,7 @@
 import { ControlValueAccessor } from "@angular/forms";
-import { View } from "tns-core-modules/ui/core/view";
+import { View, unsetValue } from "tns-core-modules/ui/core/view";
+
+import { isBlank } from "../../lang-facade";
 
 export class BaseValueAccessor<TView extends View> implements ControlValueAccessor {
  private pendingChangeNotification: any = 0;
@@ -28,5 +30,9 @@ export class BaseValueAccessor<TView extends View> implements ControlValueAccess
  this.view.isEnabled = !isDisabled;
  }
 
- writeValue(_: any) { }
+ writeValue(_: any) {}
+
+ protected normalizeValue(value: any): any {
+ return isBlank(value) ? unsetValue : value;
+ }
 }

nativescript-angular/forms/value-accessors/checked-value-accessor.ts

@@ -34,6 +34,7 @@ export class CheckedValueAccessor extends BaseValueAccessor<Switch> { // tslint:
  }
 
  writeValue(value: any): void {
- this.view.checked = value;
+ const normalized = super.normalizeValue(value);
+ this.view.checked = normalized;
  }
 }

nativescript-angular/forms/value-accessors/date-value-accessor.ts

@@ -34,6 +34,7 @@ export class DateValueAccessor extends BaseValueAccessor<DatePicker> { // tslint
  }
 
  writeValue(value: any): void {
- this.view.date = value;
+ const normalized = super.normalizeValue(value);
+ this.view.date = normalized;
  }
 }

nativescript-angular/forms/value-accessors/number-value-accessor.ts

@@ -33,6 +33,7 @@ export class NumberValueAccessor extends BaseValueAccessor<Slider> { // tslint:d
  }
 
  writeValue(value: any): void {
- this.view.value = value;
+ const normalized = super.normalizeValue(value);
+ this.view.value = normalized;
  }
 }

nativescript-angular/forms/value-accessors/selectedIndex-value-accessor.ts

@@ -50,7 +50,8 @@ export class SelectedIndexValueAccessor extends BaseValueAccessor<SelectableView
  private viewInitialized: boolean;
 
  writeValue(value: any): void {
- this.value = value;
+ const normalized = super.normalizeValue(value);
+ this.value = normalized;
 
  if (this.viewInitialized) {
  this.view.selectedIndex = this.value;

nativescript-angular/forms/value-accessors/text-value-accessor.ts

@@ -48,6 +48,7 @@ export class TextValueAccessor extends BaseValueAccessor<TextView> { // tslint:d
  }
 
  writeValue(value: any): void {
- this.view.text = value;
+ const normalized = super.normalizeValue(value);
+ this.view.text = normalized;
  }
 }

nativescript-angular/forms/value-accessors/time-value-accessor.ts

@@ -36,6 +36,7 @@ export class TimeValueAccessor extends BaseValueAccessor<TimePicker> { // tslint
  }
 
  writeValue(value: any): void {
- this.view.time = value;
+ const normalized = super.normalizeValue(value);
+ this.view.time = normalized;
  }
 }