fix(forms): introduce checkbox required validator

Closes #11459
Closes #13364

modules/@angular/forms/src/directives.ts

@@ -24,7 +24,7 @@ import {FormGroupDirective} from './directives/reactive_directives/form_group_di
 import {FormArrayName, FormGroupName} from './directives/reactive_directives/form_group_name';
 import {NgSelectOption, SelectControlValueAccessor} from './directives/select_control_value_accessor';
 import {NgSelectMultipleOption, SelectMultipleControlValueAccessor} from './directives/select_multiple_control_value_accessor';
-import {MaxLengthValidator, MinLengthValidator, PatternValidator, RequiredValidator} from './directives/validators';
+import {CheckboxRequiredValidator, MaxLengthValidator, MinLengthValidator, PatternValidator, RequiredValidator} from './directives/validators';
 
 export {CheckboxControlValueAccessor} from './directives/checkbox_value_accessor';
 export {ControlValueAccessor} from './directives/control_value_accessor';
@@ -43,13 +43,25 @@ export {FormGroupDirective} from './directives/reactive_directives/form_group_di
 export {FormArrayName, FormGroupName} from './directives/reactive_directives/form_group_name';
 export {NgSelectOption, SelectControlValueAccessor} from './directives/select_control_value_accessor';
 export {NgSelectMultipleOption, SelectMultipleControlValueAccessor} from './directives/select_multiple_control_value_accessor';
-export {MaxLengthValidator, MinLengthValidator, PatternValidator, RequiredValidator} from './directives/validators';
 
 export const SHARED_FORM_DIRECTIVES: Type<any>[] = [
-  NgSelectOption, NgSelectMultipleOption, DefaultValueAccessor, NumberValueAccessor,
-  RangeValueAccessor, CheckboxControlValueAccessor, SelectControlValueAccessor,
-  SelectMultipleControlValueAccessor, RadioControlValueAccessor, NgControlStatus, NgNovalidate,
-  NgControlStatusGroup, RequiredValidator, MinLengthValidator, MaxLengthValidator, PatternValidator
+  NgNovalidate,
+  NgSelectOption,
+  NgSelectMultipleOption,
+  DefaultValueAccessor,
+  NumberValueAccessor,
+  RangeValueAccessor,
+  CheckboxControlValueAccessor,
+  SelectControlValueAccessor,
+  SelectMultipleControlValueAccessor,
+  RadioControlValueAccessor,
+  NgControlStatus,
+  NgControlStatusGroup,
+  RequiredValidator,
+  MinLengthValidator,
+  MaxLengthValidator,
+  PatternValidator,
+  CheckboxRequiredValidator,
 ];
 
 export const TEMPLATE_DRIVEN_DIRECTIVES: Type<any>[] = [NgModel, NgModelGroup, NgForm];

modules/@angular/forms/src/directives/validators.ts

@@ -5,7 +5,7 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {Directive, Input, OnChanges, SimpleChanges, forwardRef} from '@angular/core';
+import {Directive, Input, OnChanges, Provider, SimpleChanges, forwardRef} from '@angular/core';
 import {AbstractControl} from '../model';
 import {NG_VALIDATORS, Validators} from '../validators';
 
@@ -33,12 +33,18 @@ export interface Validator {
   registerOnValidatorChange?(fn: () => void): void;
 }
 
-export const REQUIRED_VALIDATOR: any = {
+export const REQUIRED_VALIDATOR: Provider = {
   provide: NG_VALIDATORS,
   useExisting: forwardRef(() => RequiredValidator),
   multi: true
 };
 
+export const CHECKBOX_REQUIRED_VALIDATOR: Provider = {
+  provide: NG_VALIDATORS,
+  useExisting: forwardRef(() => CheckboxRequiredValidator),
+  multi: true
+};
+
 /**
  * A Directive that adds the `required` validator to any controls marked with the
  * `required` attribute, via the {@link NG_VALIDATORS} binding.
@@ -52,7 +58,8 @@ export const REQUIRED_VALIDATOR: any = {
  * @stable
  */
 @Directive({
-  selector: '[required][formControlName],[required][formControl],[required][ngModel]',
+  selector:
+      ':not([type=checkbox])[required][formControlName],:not([type=checkbox])[required][formControl],:not([type=checkbox])[required][ngModel]',
   providers: [REQUIRED_VALIDATOR],
   host: {'[attr.required]': 'required ? "" : null'}
 })
@@ -75,6 +82,30 @@ export class RequiredValidator implements Validator {
   registerOnValidatorChange(fn: () => void): void { this._onChange = fn; }
 }
 
+/**
+ * A Directive that adds the `required` validator to checkbox controls marked with the
+ * `required` attribute, via the {@link NG_VALIDATORS} binding.
+ *
+ * ### Example
+ *
+ * ```
+ * <input type="checkbox" name="active" ngModel required>
+ * ```
+ *
+ * @experimental
+ */
+@Directive({
+  selector:
+      'input[type=checkbox][required][formControlName],input[type=checkbox][required][formControl],input[type=checkbox][required][ngModel]',
+  providers: [CHECKBOX_REQUIRED_VALIDATOR],
+  host: {'[attr.required]': 'required ? "" : null'}
+})
+export class CheckboxRequiredValidator extends RequiredValidator {
+  validate(c: AbstractControl): {[key: string]: any} {
+    return this.required ? Validators.requiredTrue(c) : null;
+  }
+}
+
 /**
  * @stable
  */

modules/@angular/forms/src/forms.ts

@@ -38,7 +38,7 @@ export {FormArrayName} from './directives/reactive_directives/form_group_name';
 export {FormGroupName} from './directives/reactive_directives/form_group_name';
 export {NgSelectOption, SelectControlValueAccessor} from './directives/select_control_value_accessor';
 export {SelectMultipleControlValueAccessor} from './directives/select_multiple_control_value_accessor';
-export {AsyncValidatorFn, MaxLengthValidator, MinLengthValidator, PatternValidator, RequiredValidator, Validator, ValidatorFn} from './directives/validators';
+export {AsyncValidatorFn, CheckboxRequiredValidator, MaxLengthValidator, MinLengthValidator, PatternValidator, RequiredValidator, Validator, ValidatorFn} from './directives/validators';
 export {FormBuilder} from './form_builder';
 export {AbstractControl, FormArray, FormControl, FormGroup} from './model';
 export {NG_ASYNC_VALIDATORS, NG_VALIDATORS, Validators} from './validators';

modules/@angular/forms/src/validators.ts

@@ -64,6 +64,13 @@ export class Validators {
     return isEmptyInputValue(control.value) ? {'required': true} : null;
   }
 
+  /**
+   * Validator that requires control value to be true.
+   */
+  static requiredTrue(control: AbstractControl): {[key: string]: boolean} {
+    return control.value === true ? null : {'required': true};
+  }
+
   /**
    * Validator that requires controls to have a value of a minimum length.
    */

modules/@angular/forms/test/reactive_integration_spec.ts

@@ -39,7 +39,8 @@ export function main() {
           ValidationBindingsForm,
           UniqLoginValidator,
           UniqLoginWrapper,
-          NestedFormGroupComp
+          NestedFormGroupComp,
+          FormControlCheckboxRequiredValidator,
         ]
       });
     });
@@ -1320,6 +1321,24 @@ export function main() {
     });
 
     describe('validations', () => {
+      it('required validator should validate checkbox', () => {
+        const fixture = TestBed.createComponent(FormControlCheckboxRequiredValidator);
+        const control = new FormControl(false, Validators.requiredTrue);
+        fixture.componentInstance.control = control;
+        fixture.detectChanges();
+
+        const checkbox = fixture.debugElement.query(By.css('input'));
+        expect(checkbox.nativeElement.checked).toBe(false);
+        expect(control.hasError('required')).toEqual(true);
+
+        checkbox.nativeElement.checked = true;
+        dispatchEvent(checkbox.nativeElement, 'change');
+        fixture.detectChanges();
+
+        expect(checkbox.nativeElement.checked).toBe(true);
+        expect(control.hasError('required')).toEqual(false);
+      });
+
       it('should use sync validators defined in html', () => {
         const fixture = TestBed.createComponent(LoginIsEmptyWrapper);
         const form = new FormGroup({
@@ -2061,6 +2080,14 @@ class ValidationBindingsForm {
   pattern: string;
 }
 
+@Component({
+  selector: 'form-control-checkbox-validator',
+  template: `<input type="checkbox" [formControl]="control">`
+})
+class FormControlCheckboxRequiredValidator {
+  control: FormControl;
+}
+
 @Component({
   selector: 'uniq-login-wrapper',
   template: `

modules/@angular/forms/test/template_integration_spec.ts

@@ -19,11 +19,26 @@ export function main() {
     beforeEach(() => {
       TestBed.configureTestingModule({
         declarations: [
-          StandaloneNgModel, NgModelForm, NgModelGroupForm, NgModelValidBinding, NgModelNgIfForm,
-          NgModelRadioForm, NgModelRangeForm, NgModelSelectForm, NgNoFormComp, InvalidNgModelNoName,
-          NgModelOptionsStandalone, NgModelCustomComp, NgModelCustomWrapper,
-          NgModelValidationBindings, NgModelMultipleValidators, NgAsyncValidator,
-          NgModelAsyncValidation, NgModelSelectMultipleForm, NgModelSelectWithNullForm
+          StandaloneNgModel,
+          NgModelForm,
+          NgModelGroupForm,
+          NgModelValidBinding,
+          NgModelNgIfForm,
+          NgModelRadioForm,
+          NgModelRangeForm,
+          NgModelSelectForm,
+          NgNoFormComp,
+          InvalidNgModelNoName,
+          NgModelOptionsStandalone,
+          NgModelCustomComp,
+          NgModelCustomWrapper,
+          NgModelValidationBindings,
+          NgModelMultipleValidators,
+          NgAsyncValidator,
+          NgModelAsyncValidation,
+          NgModelSelectMultipleForm,
+          NgModelSelectWithNullForm,
+          NgModelCheckboxRequiredValidator,
         ],
         imports: [FormsModule]
       });
@@ -825,6 +840,42 @@ export function main() {
 
     describe('validation directives', () => {
 
+      it('required validator should validate checkbox', fakeAsync(() => {
+           const fixture = TestBed.createComponent(NgModelCheckboxRequiredValidator);
+           fixture.detectChanges();
+           tick();
+
+           const control =
+               fixture.debugElement.children[0].injector.get(NgForm).control.get('checkbox');
+
+           const input = fixture.debugElement.query(By.css('input'));
+           expect(input.nativeElement.checked).toBe(false);
+           expect(control.hasError('required')).toBe(false);
+
+           fixture.componentInstance.required = true;
+           fixture.detectChanges();
+           tick();
+
+           expect(input.nativeElement.checked).toBe(false);
+           expect(control.hasError('required')).toBe(true);
+
+           input.nativeElement.checked = true;
+           dispatchEvent(input.nativeElement, 'change');
+           fixture.detectChanges();
+           tick();
+
+           expect(input.nativeElement.checked).toBe(true);
+           expect(control.hasError('required')).toBe(false);
+
+           input.nativeElement.checked = false;
+           dispatchEvent(input.nativeElement, 'change');
+           fixture.detectChanges();
+           tick();
+
+           expect(input.nativeElement.checked).toBe(false);
+           expect(control.hasError('required')).toBe(true);
+         }));
+
       it('should support dir validators using bindings', fakeAsync(() => {
            const fixture = TestBed.createComponent(NgModelValidationBindings);
            fixture.componentInstance.required = true;
@@ -1291,6 +1342,16 @@ class NgModelMultipleValidators {
   pattern: string|RegExp;
 }
 
+@Component({
+  selector: 'ng-model-checkbox-validator',
+  template:
+      `<form><input type="checkbox" [(ngModel)]="accepted" [required]="required" name="checkbox"></form>`
+})
+class NgModelCheckboxRequiredValidator {
+  accepted: boolean = false;
+  required: boolean = false;
+}
+
 @Directive({
   selector: '[ng-async-validator]',
   providers: [

modules/@angular/forms/test/validators_spec.ts

@@ -50,6 +50,14 @@ export function main() {
          () => { expect(Validators.required(new FormControl(0))).toBeNull(); });
     });
 
+    describe('requiredTrue', () => {
+      it('should error on false',
+         () => expect(Validators.requiredTrue(new FormControl(false))).toEqual({'required': true}));
+
+      it('should not error on true',
+         () => expect(Validators.requiredTrue(new FormControl(true))).toBeNull());
+    });
+
     describe('minLength', () => {
       it('should not error on an empty string',
          () => { expect(Validators.minLength(2)(new FormControl(''))).toBeNull(); });

tools/public_api_guard/forms/index.d.ts

@@ -117,6 +117,13 @@ export declare class CheckboxControlValueAccessor implements ControlValueAccesso
     writeValue(value: any): void;
 }
 
+/** @experimental */
+export declare class CheckboxRequiredValidator extends RequiredValidator {
+    validate(c: AbstractControl): {
+        [key: string]: any;
+    };
+}
+
 /** @stable */
 export declare class ControlContainer extends AbstractControlDirective {
     formDirective: Form;
@@ -531,6 +538,9 @@ export declare class Validators {
     static required(control: AbstractControl): {
         [key: string]: boolean;
     };
+    static requiredTrue(control: AbstractControl): {
+        [key: string]: boolean;
+    };
 }
 
 /** @stable */