fix(if-validator): exclude individual validators from composition to …

…allow presence checks (#273)

libs/ngxtension/if-validator/src/if-validator.spec.ts

@@ -0,0 +1,134 @@
+import { FormControl } from '@angular/forms';
+import { of } from 'rxjs';
+import { ifAsyncValidator, ifValidator } from './if-validator';
+
+describe('ifValidator', () => {
+	it('should return null if the condition is false', () => {
+		const control = new FormControl();
+		const condition = () => false;
+		const validatorFn = () => null;
+
+		const validator = ifValidator(condition, validatorFn);
+		const result = validator(control);
+
+		expect(result).toBeNull();
+	});
+
+	it('should return the result of a provided validatorFn if the condition is true', () => {
+		const control = new FormControl('a');
+		const condition = (ctrl: FormControl) => ctrl.value !== 'a';
+		const validatorFn = () => ({ invalid: true });
+
+		const validator = ifValidator(condition, validatorFn);
+
+		const result = validator(control);
+		expect(result).toBeNull();
+
+		control.setValue('b');
+		const newResult = validator(control);
+		expect(newResult).toEqual({ invalid: true });
+	});
+
+	it('should return null if an array with no items is provided', () => {
+		const control = new FormControl();
+		const condition = () => true;
+
+		const validator = ifValidator(condition, []);
+		const result = validator(control);
+
+		expect(result).toBeNull();
+	});
+
+	it('should return the result of a provided validatorFn', () => {
+		const control = new FormControl();
+		const condition = () => true;
+		const validatorFn = () => ({ invalid: true });
+
+		const validator = ifValidator(condition, validatorFn);
+		const result = validator(control);
+
+		expect(result).toEqual({ invalid: true });
+	});
+
+	it('should be able to query the presence of a provided validatorFn', () => {
+		const condition = () => true;
+		const validatorFn = () => ({ invalid: true });
+
+		const validator = ifValidator(condition, validatorFn);
+		const control = new FormControl(null, validator);
+		const hasValidator = control.hasValidator(validator);
+
+		expect(hasValidator).toBe(true);
+	});
+
+	it('should return the result of a sole validatorFn provided in an array', () => {
+		const control = new FormControl();
+		const condition = () => true;
+		const validatorFn = () => ({ invalid: true });
+
+		const validator = ifValidator(condition, [validatorFn]);
+		const result = validator(control);
+
+		expect(result).toEqual({ invalid: true });
+	});
+
+	it('should be able to query the presence of a sole validatorFn provided in an array', () => {
+		const condition = () => true;
+		const validatorFn = () => ({ invalid: true });
+
+		const validator = ifValidator(condition, [validatorFn]);
+		const control = new FormControl(null, validator);
+		const hasValidator = control.hasValidator(validator);
+
+		expect(hasValidator).toBe(true);
+	});
+
+	it('should return the result of multiple provided validators', () => {
+		const control = new FormControl();
+		const condition = () => true;
+		const validatorFn1 = () => ({ bad: true });
+		const validatorFn2 = () => ({ worse: true });
+
+		const validator = ifValidator(condition, [validatorFn1, validatorFn2]);
+		const result = validator(control);
+
+		expect(result).toEqual({ bad: true, worse: true });
+	});
+});
+
+describe('ifAsyncValidator', () => {
+	it('should return null if the condition is false', () => {
+		const control = new FormControl();
+		const condition = () => false;
+		const validatorFn = () => of(null);
+
+		const validator = ifAsyncValidator(condition, validatorFn);
+		control.setAsyncValidators(validator);
+
+		expect(control.errors).toBe(null);
+	});
+
+	it('should return the result of a provided async validatorFn if the condition is true', () => {
+		const control = new FormControl('a');
+		const condition = (ctrl: FormControl) => ctrl.value !== 'a';
+		const validatorFn = () => of({ invalid: true });
+
+		const validator = ifAsyncValidator(condition, validatorFn);
+		control.setAsyncValidators(validator);
+
+		control.setValue('b');
+
+		expect(control.errors).toEqual({ invalid: true });
+	});
+
+	it('should be able to query the presence of a provided async validatorFn', () => {
+		const condition = () => true;
+		const validatorFn = () => of({ invalid: true });
+
+		const validator = ifAsyncValidator(condition, validatorFn);
+		const control = new FormControl(null, { asyncValidators: validator });
+		const hasValidator = control.hasAsyncValidator(validator);
+
+		expect(hasValidator).toBe(true);
+	});
+});

libs/ngxtension/if-validator/src/if-validator.ts

@@ -15,13 +15,24 @@ export function ifValidator(
 	validatorFn: ValidatorFn | ValidatorFn[],
 ): ValidatorFn {
 	return (control: AbstractControl) => {
-		if (!validatorFn || !condition(<FormControl>control)) {
+		if (!condition(<FormControl>control)) {
 			return null;
 		}
-		const validatorFns = Array.isArray(validatorFn)
-			? (validatorFn as ValidatorFn[])
-			: [validatorFn];
-		return Validators.compose(validatorFns)?.(control) ?? null;
+
+		if (!Array.isArray(validatorFn)) {
+			return validatorFn(control);
+		}
+
+		if (validatorFn.length === 0) {
+			return null;
+		}
+
+		if (validatorFn.length === 1) {
+			return validatorFn[0](control);
+		}
+
+		const composed = Validators.compose(validatorFn);
+		return composed ? composed(control) : null;
 	};
 }
 
@@ -33,7 +44,7 @@ export function ifAsyncValidator(
 	validatorFn: AsyncValidatorFn,
 ): AsyncValidatorFn {
 	return (control: AbstractControl) => {
-		if (!validatorFn || !condition(<FormControl>control)) {
+		if (!condition(<FormControl>control)) {
 			return of(null);
 		}